So... tell us about a time that you put your foot in your mouth or did something well-meaning but absolutely foolish that bounced back in your face. Or, alternatively, a situation where things could have gone horribly wrong but you rectified it at the last minute.
On Tuesday, I was asked to take an envelope full of cheques and pop it in to the deposit slot at the bank. Only thing was, I didn't know where the bank was, so I had already walked past it before I spotted it. I considered going on to the gym and dealing with it on the way back to the office but I could see that I was risking a horrible sitcom incident (or perhaps the plot of Burn After Reading) where I would leave the envelope in the locker, have it stolen and end up looking very stupid in front of my workmates, not to mention potentially being fired. So I played it safe and backtracked to the bank first.
On the other hand, today I was very stupid indeed. Every second thursday one department puts on a lunch. The receptionist put a note in my calendar telling me that my department was due to put it on. I'm the only one in my department with a Windows computer, so I was the only one who received it. I told my workmates about it and one of them put in a huge amount of effort to put it together... only to find out that we were actually meant to do it in late November! The receptionist had just been putting in the next couple of month's notices in the calendars and I hadn't looked close enough. So me = stupid indeed.