We all know we occasionally do some stupid things, of which we later think: "I shouldn't have done that", for a great picture or otherwise. Hereby, I'd like to open the votes for the most stupidity done in relation to not such a great picture.
I'd expressly NOT want to nominate Lord Awesome:
Because what he dis was INSANELY stupid, but his picture was WAAAY cool. The same goes for all the crane climbers.
Also, it doesn't count if you went up/under there for just exploring - curiosity may have played a role, but the target must've been to take a great picture (and you failed at that).