I read somewhere that most humans are hardwired to focus on negatives, not positive, but that we can retrain ourselves, building new neural pathways and adopting new behavior habits. I know it's true, even with occasional relapses. Hang in there and just work on it! If you have a bad time of it now and again, just get back up on that horse and ride, even though it's hard. It's pure worth it. Actually hard work, tho. Someone also told me once it's easier to be regularly miserable. What an existence, although I think this may be true!