Studies show that people who witness the act of gratitude get affected positively towards the grateful person as well as the person who is being thanked (benefactor).

They see the grateful person as someone who is kind, and who notices when other people do kind things and takes the time to acknowledge them, making them socially desirable. People also warm up towards the person that is receiving the gratitude, as it is signaled as a person who is effective at being supportive or helpful.