What is Entertaiment?
A broad category of activity that includes sports, games, drama, music, dance, and a variety of other forms. It may include entertainment of a more formal nature, such as ceremonies, celebrations, religious festivals, or satire. Entertainment is often used for the purpose of providing pleasure or amusement, but it can also serve a more serious purpose such as education, moral instruction, or cultural enrichment.
The word entertainment comes from the Medieval Latin inter tenere, a contraction of the prefix inter- meaning “inside” and the suffix tenere, derived from the Indo-European root ten, which means to hold inside or stretch out. Entertainment is now the most popular form of mass media in the world.
I think that entertainment hits on points that the brain was evolved to deeply react to, such as backstabbing, murders, etc. These themes provide a good feeling since the brain releases seratonin and dopamine as a result of entertainment.