I'm not by nature an optimist, but I've learned to trick myself. One thing that works for me is to focus on the best things that have happened that day (or in some cases, the 10 things that were the least awful). "If you can't be happy for what you have, be happy for what you don't have." So join the list, post your 10 best things, and create a mindshift. I know you can do it.