My mother always says 'It's just as easy to be nasty to people as it is to be nice to people'. Living in a way that creates positive moments with the people you meet and encounter can save lives and save yours.
Taking the extra moment of time to converse on something positive going on in your life helps others see the positive in their life. This can be simple like eating a burger at a fast food restaurant.
Telling someone that you had a positive experience and could afford to enjoy that moment is something that brings people back to what's going good in their life.
It also brings recommendations to others so they too can experience a joyful moment.