As for the five things that corrupt the heart, they are those that are referred to:

1. Mixing too much with people,
2. Wishful thinking,
3. Being attached to anything other than Allah,
4. Eating one’s fill, and
5. Sleeping too much.

These five are the greatest corrupter of the heart.

Ibn Qayyim, Madaarij al-Saalikeen (1/453).