As with all stressful situations, you first need to calm yourself. I find that listening to ambient music and attempting to empty your mind by listening intently to the music can provide perspective and show you that time will continue to flow, and with it, your problems will also eventually run their course.
Rationality is your friend, violence and anger are not. I know it may be difficult, but attempt to understand exactly and logically what is happening and how it is happening. The trick here is to gain perspective and also to look for answers to your problems. There is a way! You must find it!
Try to picture yourself at the top instead of your boss. Pretend that you're the one giving orders and direction. Picture yourself as the leader of your branch/department or even the CEO of the whole firm. Remember, it is not the firm that is your stress source, nor the work, it is the people who you must share your existence with.
Some problems follow you from home. I have seen this time and again. If something is misaligned at home it will affect you at work no how much you deny it. Make a list of your goals and dreams and ensure that what you're doing is in line with these.
Try to meditate on your problems by thinking from a third person perspective. Instead of saying, "Boss, Jim is so mean to ME! Why is he so mean to ME!?"(saying this is accusatory and will lead to more stress and feelings of anger) Try saying, "Boss Jim is so mean to ( fill in your name here). Why is he so mean to ( your name )?. This is not an act of dissociation but an attempt to gain a better perspective of the issues you are facing. You could even draw a picture of the scene if you want. You may be surprised at what you see.