I love the exercises in the book Ask and It Is Given for overcoming anger. Basically you aim to find the best-feeling thought from where you are now and focus on it. This helps you gradually move up the levels of consciousness scale:
http://www.stevepavlina.com/blog/200...consciousness/
If you're angry, you can focus on moving up to the level of pride and maybe courage. To do this you redirect your anger in the most positive direction you can think of, even if it doesn't seem that positive in an absolute sense. Relatively positive is all you need.
Doing your workout was a perfect example -- you turned your anger into pride of accomplishment. In other words you raised your level of consciousness. But when you returned to those angry thoughts, you sank back down again. All you need to do is to repeat the process to get back to pride, and from there push on towards courage.
For example, you could direct the energy of anger into "getting mad" at little problems in your life and tackling them until you start to feel pride, such as doing some home repair or organizing projects.
When you're in a state of pride, you can progress to the level of courage by directing your energy into doing something that scares you a little. Tackle a project you've been putting off.
This way you channel your anger into positive activity and raise your level of consciousness.