Try to remember that even if nothing seems funny right then, humor is emotional chaos remembered in tranquility. Look forward to the day when you will recount the situation and laugh. Besides keeping you from blowing your stack, a sense of humor will endear you to both your co-workers and the public. This doesn't mean that you need to start reading joke books an hanging out at the comedy club trying to steal material. It just means that you try to have fun at all times and try to see the funny side of all situations. You don't even need to mention the funny side. Just the fact that you can recognize it will change your demeanor, make you happier, and make people more comfortable around you.