Another benefit on happiness:

Imam Ibn Qayyim rahimahullah said:

من علامات السعادة والفلاح أن العبد كلما زيد في علمه زيد في تواضعه ورحمته وكلما زيد في عمله زيد في خوفه وحذره. وكلما زيد في عمره نقص من حرصه. وكلما زيد في ماله زيد في سخائه وبذله. وكلما زيد في قدره وجاهه زيد في قربه من الناس وقضاء حوائجهم والتواضع لهم

“From the signs of happiness and success is that every time a servant increases in knowledge he increases in humility and mercy. Every time he increases in knowledge he increases in fear and caution. Every time he increases in age he decreases in his eagerness [for the worldly life]. Every time he increases in wealth he increases in generosity and spending. Every time he increases in ability and honor he increases in nearness to the people, fulfilling their needs and humility in dealing with them”

[Kitab al-Fawaaid pg. 155]

Translated by

Faisal Ibn Abdul Qaadir Ibn Hassan
Abu Sulaymaan