On crowded public transport, smile manically at the people around you until your cheeks start to hurt. It's impossible to be unhappy whilst waggling your ears. Stare intently at people's jugular veins or the place where their ears join onto their heads. You'll be surprised by the increased respect you get. Every day, shut yourself away for a while and attend to your own needs.
Masturbation is nature's own way of easing stresses and strains.
Do it for at least an hour a day. If you have a disagreement with someone, don't have it out there and then. Arrange to meet later to discuss it when you're both in a calmer frame of mind. Get there early and be waiting for them with a baseball bat. It sounds harsh, but avoid people who are good-looking or successful or naturally happy, as they can be very depressing to be around.