The Five Heart Corrupters are:
1. Excessive socializing;
2. Wishful thinking;
3. Attachment to others besides Allaah;
4. Eating to one's fill;
These five factors are the greatest corrupters of the heart. In this article I will mention the effects that are common to all of them as well as those effects that are unique to each of them.
Know that the heart is on a journey to Allaah, Most Great and Glorious, and to the world of the Hereafter, and [that it is able to] discover the path of truth as well as the faults of the soul and of deeds. Its path is traversed with its light, life, strength, health, determination ('azm), the soundness of its hearing and sight, as well as the absence of distractions and impediments from it.
These five (corrupters) extinguish its light, distort its vision, muffle its hearing, if they do not deafen it, dumbfound it, and weaken its powers/strengths altogether. They weaken its health, slacken its drive, halt its decisions, and reverse it (sending it backwards). And if one does not sense it, his heart is dead – as wounding a corpse does not inflict pain. They are impediments that prevent it from achieving its perfection, and prevent it from arriving to what it was created for, and making its pleasure and happiness ibtihaah and its enjoyment in arriving to it.
For there is no pleasure, sweetness, ibtihaaj, or perfection except by knowing Allaah and loving Him, peace in remembrance of Him, happiness and ibtihaaj in being close to Him and desiring to meet Him. This is (the heart's) early paradise. As there will be no pleasure or success for it in the Hereafter, except by being its neighbour in the abode of pleasure in the early paradise. It has two paradises. It will not enter the second of the two if it did not enter the first.
I heard Shaykhul-Islaam Ibn Taymiyyah – may Allaah have mercy on him – say:
"Indeed there is a paradise in this world, whoever doesn't enter it will not enter the paradise of the Hereafter."
Some of those known for their love of Allaah (Al-Muhibboon) [were reported to have] said:
"The truly unfortunate people of this world are those who leave the world without tasting the sweetest thing it contains." When they were asked what it was, they replied: "The love of Allaah, to feel comfortable in His company, to desire to meet Him, turning towards Him and turning away from everything besides Him." Or some words similar to that.
Everyone who has a heart bears witness to this and knows it as a result of having tasted it. And these five matters cut [the person] off from this, block the heart from it, impede its journey, cause sicknesses and defects for which, if the sick person does not realize it, [destruction] is feared.
The First Corrupter: Frequent Socializing
The effect of frequent socializing is that it fills the heart with the smoke of anfaas of humans until it becomes black,  causing it to be scattered, torn apart, worried, upset, and weak. It causes it to carry what it is unable to from mu'nat evil companions and waste what is beneficial for it, by becoming too preoccupied with evil companions and their matters to attend to what is beneficial. (The heart instead is busy with) scattered thoughts in the valleys of their requests and wishes. So what remains of it for Allaah and the life to come?
How many adversities has mixing with people brought and how many blessings has it repelled? [How many] trials has it caused and opportunities disabled, raziyyah caused to fall in baliyyah. Is aafah the downfall of people caused by other than people? Did Aboo Taalib at the time of his death have anything more harmful to himself than evil companions? They remained with him until they blocked him from the one statement that would have guaranteed him eternal pleasure.
This socializing based on love in this world, the fulfillment of desires from others, will change into enmity when the realities become manifest, and some of those who socialized will bite their hands in regret as the Almighty said: "On the Day when the sinner will bite his hands saying: If only I had taken a way to the Messenger. Woe to me, if only I hadn't taken so-and-so as a close friend. He misguided me from the Remembrance after it came to me.' And Satan is forever a deserter of humans in their time of need." (Soorah al-Furqaan, 25: 27-9)
He also said:
"Close friends on that Day will be foes of each other except the God-fearing." (Soorah Az-Zukhruf, 43: 67)
And He said:
"Indeed what you have taken besides Allaah is only idols. Love between you is only in this world, but on the Day of Resurrection you will disown each other and curse each other and your abode will be the fire and you will have no helpers." (Soorah al-'Ankaboot, 29: 25)
That is the state of those who share goals, they love each other as long they help each other to achieve it. But if the goal is cut off, it is followed by regret, sadness and pain, and that love will change into hatred, cursing, blame of one another, and the goals change into unhappiness and punishment, as is witnessed in this life in the states of those who share in failure, if they are caught and punished. Each supporter of falsehood, friendly regarding it, their mutual love must eventually change into hatred and enmity.
The useful defining principle in the matter of socializing is that one should mix with people in [acts of] goodness like Jumu'ah, the 'Eeds, Hajj, learning knowledge, Jihaad, giving advice; and avoid them in [acts of] evil, as well as unnecessary permissible things. If necessity requires mixing with them in evil and avoiding them is not possible, then beware, beware of agreeing with them. And be patient with their harm, for they must harm him if he does not have power or a helper. However, it is harm followed by honor and love for him, respect and praise for him from them, the believers, and from the Lord of the worlds.
Thus, patience with their harm is a better ending and a more praiseworthy conclusion. If necessity requires mixing with them in unnecessary permissible things, he should strive to transform the gathering into one of obedience to Allaah if it is possible, he should encourage himself and strengthen his heart, and not pay attention to the satanic whisper of discouragement which will prevent him from that, that this is Riyaa' [showing off], a love of displaying one's knowledge and state, etc., he should fight it and seek help from Almighty Allaah and try to affect them as positively as he can.
If destiny prevents him from that, he should remove his heart from among them the way a hair is removed from dough. Among them he should be present yet absent, close yet far and asleep yet awake. He should look at them and not see them, hear their words but not be conscious of them, because he has removed his heart from among them and ascended with it to the uppermost hosts (Al-Mala'il-A'laa) glorifying [Allaah] around the throne along with the pure celestial spirits. How difficult this is and trying for the souls, [yet] it is easy for whoever Allaah makes it easy. Between a slave and [that state] is that he be truthful to Allaah – Blessed and High – continually seeking refuge in Him, and that he throw his soul on [Allaah's] doorstep in humility. Nothing will help him to do that besides sincere love, continual remembrance of Allaah with the heart and tongue, and avoidance of the remaining four corrupters to be mentioned. He will achieve this except with righteous preparation and strong material from Allaah – Most Great and Glorious – and a truthful conviction, and freedom from attachment to other than Allaah, Most High. And Allaah Almighty knows best.
The Second Corrupter: Riding the Sea of Wishes
It is a sea without shores. It is the sea ridden by the bankrupt of the world. It is said:
Wishes are the capital of the bankrupt, and its travel provisions are the promises of Satan, and impossible imaginations and falsehood. The wealth of false wishes and false imaginations continue to play with one who rides them the way that dogs play with a corpse. They are the supplies of every disgraced, humiliated, low soul, having no conviction to achieve external realities. So it turned away from them with mental wishes. And everyone has it according to his state: From a wisher for power and authority, or travel and international travel, or wealth and valuables, or women ... The wisher imagines an image of what he desires in his mind, and he succeeds in creating it and takes pleasure in capturing it. While he is in this state he suddenly awakes to find his hand chained. (p. 446)
The one who has lofty/high conviction [himmah] his hopes pivot around knowledge and faith and deeds which will bring him closer to his Lord. These wishes are faith, light and wisdom, while the wishes of those are deception and delusion.
The Prophet (p) praised the one who wishes for good, and made his reward in some things similar to that of the one who actually does it, like the one who says: If I had money I would do as so-and-so does who fears his Lord regarding his wealth, strengthening family ties with it, and extracts from it what is required. He said: "Regarding reward, they are equal."  The Prophet (p) wished in the Farewell Pilgrimage that he was doing Hajj Tamattu' and khalla and that he did not take a sacrificial animal with him,  as he was doing Hajj Qiraan. So Allaah gave him the reward of Qiraan which he did and the reward of Tamattu' which he wished for and combined for him both rewards.
The Third Corrupter: Attachment to Other Than Allaah
This is the absolute worst of the corrupters. There is none more harmful than attachment to other than Allaah, nor more able to cut the heart off from Allaah, and block it from what is beneficial to it and what will bring it true happiness. If a heart becomes attached to other than Allaah, Allaah makes him dependent on what he is attached to and he will be betrayed by it and he will not achieve what he was seeking from Allaah as long as he is attached to other than Allaah and turning to others besides Him. Thus, he will not obtain what he sought from Allaah nor will what he was attached to besides Allaah bring it for him:
"And they have taken gods besides Allaah that they might give them honor, power and glory. No. But they will deny their worship of them and become opponents to them." (Soorah Maryam, 19: 81-2)
"And they have taken besides Allaah gods hoping that they might be helped. They cannot help them but they will be brought forward as a troop against them." (Soorah Yaaseen, 36: 74-5)
The person most betrayed is the one who is attached to other than Allaah. For what he missed of benefits, happiness and success is far greater that what he obtained from those to whom he was attached, and it is exposed to disappearance and loss. The example of one attached to other than Allaah is like one seeking shade from the heat and cold in a spider's web (home), the weakest [wahn] of homes.
In general, the basis of idolatry and the foundation on which it is built is: Attachment to other than Allaah, and for the one who does so there is condemnation and betrayal, as stated by the Almighty:
"Do not set up with Allaah any other god or you will sit down reproved and forsaken." (Soorah al-Israa, 17: 22)
"Reproved" without anyone to praise you, "forsaken" without anyone to help you. As some people may be forced while being praised, like one is forced by falsehood, and he could be forsaken while being helped [by Allaah], like one forced and falsehood has gained the upper hand over him, and he could be praised and supported like one becomes established and gains dominion by way of the truth. The idolater attached to other than Allaah, his is the vilest category, neither praised nor supported.
The Fourth Corrupter: Food
The corrupter of the heart is of two types:
One of them is that which corrupts it by itself like the forbidden which are two types:
· Forbidden relative to Allaah like carcasses, blood, pork, wild animals that kill with the canine tooth  and birds that kill with claws.
· Forbidden relative to Allaah's slaves, like stolen, maghsoob, kidnapped, and what is taken without the permission of the owner either by force or by shame and blame.
The second is what corrupts as a result of its quantity and its exceeding limits, like wasting permissible things, excessive filling of the stomach, for it makes acts of obedience burdensome and it preoccupies the heart... chasing after belly desires and trying for it until it captures it. If it captures it he becomes preoccupied with following its activities and protecting the self from its harm, and being hurt by its weight, and it strengthens the elements of desire. It paves paths for Satan and expands them, for he moves among humans in the veins. Fasting narrows its passages and closes his paths and filling the stomach paves paths and widens them. Whoever eats a lot, drinks a lot, sleeps a lot and loses a lot. In the famous hadeeth:
"No human fills a container worse than his stomach. Two small portions of food to straighten his backbone are sufficient. If he must [eat more], then let it be a third for food, a third for drink and a third for breathing." 
It is said that [on one occasion] Iblees – may Allaah curse him – met Yahyaa, son of Zakariyyaa – peace be upon them – and Yahyaa asked him: "Did you take anything from me." He replied: "No, except one night when food was presented to you, I made it so desirable to you that you ate your fill and you went sleep without making your regular supplications." Yahyaa said: "I swear by Allaah that I will never eat my fill again." Iblees then said: "As for me, I swear by Allaah that I will never advise another human again."
The Fifth Corrupter: Excessive Sleep
It deadens the heart, makes the body heavy, wastes time, and gives birth to a lot of negligence and laziness. Some [types] of sleep are extremely disliked, and some are harmful to the body. The best form of sleep is what takes place when there exists a strong need for it. Sleep at the beginning of the night is more praiseworthy and beneficial than at the end of the night, and sleep in the middle of the day is better than at its beginning and end. The closer sleep is to the beginning and ending of the day the less the benefit and the more the harm. [This is] especially the case for sleeping in the after noon ('asr) and sleeping at the beginning of the day, except for one who stayed awake all night.
And among the disliked aspects, according to the scholars, is sleep between Salaatul-Fajr and sunrise, for it is a time of special reward. For that time escape, among the saalikeen (travellers), is a great loss. Even if they traveled all night they would not allow sitting down from the journey at that time until sunrise, because it is the beginning of the day and its key. [It is] the time for provisions to be sent down [and distributed], the time for obtaining portions and the descent of blessings, and from it the day is established. The ruling regarding the whole day is [based on] the ruling regarding that portion. One should only sleep at that time if one is forced.
In general, the most balanced/moderate (a'dal) and beneficial form of sleep, is sleep during the first portion of the night and the last sixth of the night. According to medical practitioners, the length of the most balanced form of sleep should be eight hours. In their view, more [sleep] than that or less than that will cause deviation in one's natural disposition according to it.
Among the forms of sleep that are not beneficial also, is sleep in the first part of the night shortly after sunset until the darkness of 'Ishaa goes. The Messenger of Allaah (p) used to dislike it. So it is disliked according to the Sharee'ah and naturally.
As excessive sleep causes these defects, putting aside sleep and abandoning it causes other major defects like bad temperament, dry personality and a warped disposition, as well as drying up of the humors  which aid in understanding and work, and it leads to illnesses which will prevent one afflicted from benefiting either with his heart or body.
Existence [of the world] was established on the basis of justice ('adl), so whoever adheres to moderation has grabbed his portion of the confluence of good.