From Scott Adams' Micro Lessons. Find an index of his lessons here.
One thing I heard last week about what causes stress is inaction. Now, in some situations we are constrained to act because the losses from acting could be disastrous to yourself, those you love, and those in your cartel. But if you've got items remaining on your "To-do" list, then get those done and that will reduce the stress caused by inaction. Doing nothing can be stressful.