Offices today tend to be open - cubes with low or no walls. This level of exposure can encourage transparency, but can also put you on display in fragile moments when you are stressed or upset.
The next time you feel like you might lose your cool (and who hasn't had those moments?), take note of where you are. If you might be observed by others, take a deep breath or a drink of water. If that doesn't do the trick, get outside.
In these new, open work spaces, it's critical to maintain professionalism by being calm and supportive of others, and by doing your venting somewhere private.