OK, so you're having a bad day at the office. Is there anything you can do to turn it around? According to this article, there most likely is.
The first thing you need to do is accept that you are having a bad day. Being in a bad mood doesn't mean you are not a good person. Trying to force yourself into a good mood rarely works and can probably make your mood even worse. So, learn to accept.
Don't try to keep your mood a secret. According to the author of the article, "Simply say, 'Listen, I'm in a really sour mood today. I'm not sure why, but it's nothing you've done. If I do bite your head off, I'm apologizing in advance."
When you have a moment, look inside yourself. Try to figure out if there are factors that could lead to your bad mood. Maybe you just slept badly. Are there factors in your life that could be contributing? Learn to manage your emotions.
Some of the other things you can do are: thinking about good things, letting the bad mood pass, and taking some time in quiet and by yourself. The article writer also suggests making a decision to "start your day over now."
Whether or not any of these things will really make you feel better is up to you, of course. If what makes you be in a bad mood is your job, there may be no help beyond finding a new one. Still, maybe taking a few moments of quiet and reflection can at least make things easier on those who have to work with you.