Dwelling

I have this mood poisoning habit, I hate it but I don't know how to stop. My problem is I dwell too much, on little things, big things and stupid futile things. It's annoying, why can't I just forget about it and move on. Instead I just think about it a lot. Dwelling on it until it completely ruins my mood.  It's not good to dwell on things, you're just setting yourself up to be put in a bad mood. I've noted that a lot of what we feel is self inflicted. How much more clear would our thoughts be if we didn't worry about simple things, or over analyse? It's good to just let it go sometimes.