I think the act of kindness infect people and influence their life. According to the research, it said that the smile will make people positive and happy. Thus, In my opinion, we should frequently smile at friends and to parents. Also, do some act of kindness such as opening the door for the old people, saying have a nice day to workers, etc. This video clearly tells hat the kindness is like a Boomerang because it returns back.
This video will help you to learn more about the results of the act of finding.