Alcohol.

One thing I have noticed about alcohol and myself is that it causes an undesirable swing to my emotions. (Yes, I realize that it is a depressant.) I find that the environment and people that I am around at the time are the determining factors in my mood. If I'm in a quiet setting, I will likely feel sleepy. If I'm at a party, then I'll feel energized, laugh a lot, babble non-stop and then babble some more until the evening ends. Unfortunately, if I'm in a setting where I am displeased with a tiny thing, the little issue magnifies itself and I fall into a state of unhappiness which doesn't go away for hours and hours and hours...I bite my tongue though, I do quite well getting into sober trouble that I don't wish to add to that drunken trouble =p