Heard this tonight at my Stress Management Class: "Stress is being in conflict with what is..." (Eckhart Tolle) I like that....It's true.
Sometimes stress is worth it, if you can change what is to something more in harmony with your disposition. Trick is knowing when you can, when you can't, or when you can, but it's not really worth the effort it would take. Actually, that last one is about the hardest to deal with.