Anger creates stress hormones which actually make you gain weight, or at least keep from losing it! I lost weight and exercise at the Y about 4 days a week and I know that you just need to keep at it, even if you don't feel like exercising. You feel better in the end. If I don't feel like going to a class, I go use the treadmill and take my IPod and listen to a book on it to pass the time.
I also think that about 90% of how we age and the illness and diseases we get, has to do with our lifestyle choices and to me, that is motivating -to think that I have a choice, so I choose to eat healthy and exercise.
Visualization is helpful and reading motivating books. I think if we want to change things about our lives, we have to start by changing our thoughts.
There are also websites dedicated to finding support and "buddies" out there. I really liked Spark People.com
which is a totally free website where you can track exercise and calories, join forums and has lots of good weightloss info.