Al-Hasan al-Basree rahimahullaah said :
The true reality of good character is: Doing good to others, withholding from harming, and having a cheerful face;
and al-Qaadee `Iyaad said:
It is to associate with the people in a beautiful manner, to have a cheerful face, to show love for them, to show compassion for them, to tolerate the harm they cause, to be forbearing with them, to have patience upon disagreeable things, to abandon having pride or being arrogant towards them; and to avoid harshness, anger, and taking them to account.
Imaam Ahmad ibn `Umar al-Qurtubee -rahimahullaah- (d.656 H)
in his explanation of the Abridgement of Saheeh Muslim, al-Mufhim (6/116-117)