What is the reason for overly sad movies like Fault/Stars?

I will never ever understand this. I hate crying. your throat closes up and gets sore and you look absolutely dreadful.  I would like to know how anyone can spend 15-20 dollars to see an overly sad movie? Real life already sucks donkey balls, I just don't see why/how this is entertainment? entertainment you PAY TO SEE?  

someone please explain.