Once a month, approximately. I get really bummed out and the smallest stuff sends me off the deep end. Had trouble getting a topic approved for a paper this week and I was all doom and gloom. No big deal under regular circumstances, but when I'm in my moods, hey, anything goes.
I debate the pros and cons when I get like that. So far the cons are winning, occasionally only because I haven't devised a method to not leave any clean up. Even when I'm downtrodden I don't want to be a menace to my family. 'Twould be rude.
On the flip side, I ride a motorcycle and have a few close calls every week (Arizona drivers, man) so I could die any day through (little to) no fault of my own anyway.