One time my key snapped and I didn't have a backup so I had to go to Canadian Tire and buy the biggest set of bult cutters they had. After like 2 hours of going at it with all my strength the shackle of the padlock finally cut, but on the wrong damn side! After about another hour I got through the proper side of the shackle and got my bike free. from all this effort I managed to destroy the bolt cutters by completely bending the steel arms inwards so that now the blades won't even touch when you try to cut with it. I got how with the lock and was bored, so I tried to see if I could get the key piece out, only to find I could still unlock the lock just by grabbing the key with pliers and twisting.

Anyways, moral of the story is, I'm not strong enough to be a bike thief.