How beautiful for smile to spread in Muslim societies! Smile eases lots of pains people experience at every moment. It is not a condition for the one to be free from worries to smile, the Prophet (PBUH) used to smile constantly though sorrows surrounded him always.

(At-Tirmidhi narrated on the authority of `Abdullah ibn Al-Harith ibn Jaz` that he said: (None was more smiling than the prophet.

The prophet (PBUH) held smile a valuable act that the Muslim is rewarded for it.

The Prophet (PBUH) said: (Smiling at your brother's face is an act of charity

https://islamstory.com/en/artical/3407663/6-sunnah-smiling