People make their own reasons for being unhappy. It is observed that most people do more to remain unhappy rather than to feel happy. There are few generic reasons which make most people unhappy.
From the below link, find out the top reasons that makes people unhappy.

He may or may not have been cheating for some time but has nevertheless left you for another woman. She may be younger, older, prettier, and more fun or not. You don’t actually know, but your imagination is driving you crazy. You imagine them talking about you behind your back, scheming, making mad, passionate love in your bed, in the car, on the beach and almost every other place your eye can see. While you’ve “sort of” accepted the breakup of the relationship, you’re burning with desire for revenge.

It's good to be happy. It lowers stress, makes the day go quicker, and makes people around you happy. There's nothing more satisfying than being around someone happy.

This webpage is brought to you by famous authors and other persons throughout history. They give their own personal view on what happiness and being happy is all about.