Why do people do this to themselves?

Exactly... can someone please tell me why people do this to themselves? Sad movies based on real events or even those based on fiction have been around since not long after movies began to be made.  They have a audience... but I just don't get it!  Isn't there enough misery and heart ache in this world? Do people actually enjoy watching these heart breaking movies? What does it add to their life? Does it add meaning? Does it allow them to feel like their own life is not so bad? Seriously, I just don't get it!  Watching a person who is watching such a movie is like watching someone on an emotional roller-coaster.  Happy, Sad, Happy, Sad, distraught and in tears, oh yeah Happy again.  Do they revel in the misery of others? Or is it a way to actually feel emotion, when so many people appear to have lost the ability to?  Maybe there is something of value in these movies, however after watching Watership Down at the age of 7, and having my heart break over a poor bunny, I know that I don't need that.  I feel enough emotion every day whether it be happiness or sadness, love, joy or heartache, that I just don't need to add to it with these movies.