Smiling and showing happiness in front of a believer

Hazrat Fatima Zehra (sa) Said:

اَلْبُشْرى فى وَجْهِ الْمُؤْمِنِ یُوجِبُ لِصاحِبهِ الْجَنَّةَ، وَ بُشْرى فى وَجْهِ الْمُعانِدِ یَقى صاحِبَهُ عَذابَ النّارِ.

Smiling and showing happiness in front of a believer leads a person to enter Paradise, and the result of smiling in front of your opponent and your enemy (just to soften his heart and reduce his evils towards you personally or in general) will be the reason for you to find safety and peace and be away from the punishments of Doomsday.

(Mustadrak al-Wasail: Vol. 12, p. 262, Biharul An’war: Vol. 72, p. 401, H. 43).