I used to feel this same way, so I researched it on my own and came up with my own conclusion. Think about it like this: Say that a kitten is taken in by a mother dog. The kitten is obviously misplaced, by nature, but after the kitten is grown a little more, it feels right at home with it's adopted brother and sister puppies. The kitten had become so used living with dogs, like a dog, that the kitten wouldn't feel as comfortable with cats, despite how much cat-friendly a family of cats would be. Human emotions are very similar. When a person is sad for an extended period of time, that person becomes comfortable with feelings of sadness. But even though there's no reason to feel sad, these people would rather stay in their own comfort zones, and remain sad. When I found this out, I was a little annoyed with myself, that I could fall victim to my own fear. A fear of being happy. That's no way to live, you know? Listen to some happy songs and look at your life. imagine all of the good that you have. Maybe it's that you have a warm home, or a loving boyfriend, or trustworthy friends, or anything else, really. Look up some funny jokes and let yourself laugh. Just let yourself get used to happiness, it'll all be ok. Sometimes I still find myself listening to a sad song even when I'm not sad. Sometimes, we all need and escape to the deepest parts of our own comfort, just don't be afraid that feeling other things will fail. I think that this starts with being shot down for something. Maybe you asked somebody out and they said no, or you were turned down in a job interview too many times, or anything. This tells us, subconsciously, that being hopeful results in failure. While is certainly not that case. Hope I helped.