Optimist, I tend to make sure I avoid all negative thought altogether.
Why the fuck would I want to be down and unhappy all the time when I can get my shit together and make everything awesome and have a great day? It just seems so futile trying to see the worst in people, in things, in life. There is no reward, it's a pointless stream of negativity.
So optimism makes sense when you look at life and decide you want to be happy. Problems, regardless of gravity, will end up resolved so there's little need to worry about them.