I did this on my first ride around the block. I heard a little *clink* as I approached my corner, thought nothing of it, and kept going. I facepalmed pretty hard when I got back to the garage and looked at it. Then I spent the better part of an hour trying to find the damn thing in the dark (this was all at around 2:00AM).

I've put my toeclips on backwards or upside-down at least three times.

It took me a pretty long time to screw my pedals on the first time because "WTF, they're threaded the wrong way!"