On my way home yesterday, I stopped to buy some fruit and stuff, and after I had everything loaded and secured, I went to unlock the padlock, and my key sheared in half.
First, I put my milk back so it wouldn't get too warm while I figured out what to do. I could have walked home and come back with a hacksaw, but it's at least a half an hour walk, and I was already late coming home. So I asked the manager if they had a hacksaw or bolt cutters--it's a small store and they know me--but of course they didn't. They did bring out a tool box, though, and I found a pry bar and hammer, and decided to give them a try. No luck, especially as I didn't want to damage my bike or the wooden pillar the chain went around.
But I remember having read that you can pick a padlock using a thin piece of metal cut out of a soda can. (I even tried it on one of my locks once, to see how it worked, but hadn't been able to manage it.) So I asked them for an empty soda can, and then went back to the toolbox to get the aviation snips.
But while digging through, I came across a cold chisel, and I figured that would be easier than trying to pick the lock. So I sit outside the store for awhile, with people walking in and out past me, hammering away at the chisel, until I cut through a link in the chain. Then run in quick to grab the milk, put away the tools, say thanks, and end up home only fifteen minutes later than I would have been.