A few years ago, I came out of the gym and found my bike sandwiched between the bike post and somebody else's bike. The idiot had locked his bike to the post as well, but put his u-lock through my bike's main triangle.
There was a hardware store near by, I walked over and bought a hacksaw. I went back, and sawed the other bike in half and got my bike out. I wasn't going to waste my time trying to cut the u-lock.