I have gotten to a point in my life where there are two key factors that have a major impact on my general well-being: sleep and exercise. When I don't get enough of either, I get cranky, stressed, have trouble focusing, and generally get less accomplished. For me, "enough" sleep seems to be at least 7 hours per night and "enough" exercise means not going any more than 3 days without a decent workout. Sleep and exercise can cure almost anything for me - I think more clearly and stressful things fall into perspective - and as an added benefit, exercise helps me sleep better and sleep improves my workouts (even making it somewhat likely that I can work out before work!). All in all, sleep and exercise keep me calm and sane in many ways. I highly recommend it.