Entertaiment is something that makes you feel good, gives you pleasure. It stimulates your brain to realease seratonin, dopamine and other chemicals that make you feel happy. Entertainment often hits the points that our brains was shaped to deeply react to in order to understand our world. These points can be backstabbing, murders or other aspects in the social world that we were shaped to understand.
Entertainment can be in the form of movies, tv shows, music, books, sports, or games. It can also be in the form of dance, theatre, comedy shows or visual art.