Entertaiment is something that provides diversion or amusement. It can be a form of entertainment that appeals to an individual for their own private amusement, such as choosing music or doing crossword puzzles; or it could be a banquet that is served to an audience of two or thousands. Entertainment can also be an aspect of culture, such as a ceremony, religious festival or satire.
Often, Entertainment hits on themes that our brains were evolved to react to deeply. Hence, it can cause the release of seratonin and dopamine that make us feel good. Whether it is murders, social backstabbing or other topics in the social world, Entetainment hits on those points that our brains were shaped to understand.