Acknowledge the people around you. Genuinely compliment several people over the course of the day for something they have done to help others. SDG 3, 10.
The Why?
Very often we take the little things that people do for us for granted: a stranger holds open a door, a friend listens to our complaints, a family member prepares our dinner, cleans up for us, does our laundry. By acknowledging these activities, we demonstrate to people that we appreciate their actions. If you remember the movie Avatar, its like saying to someone its nice to see you again.