Doors and locks are great. They protect you from intruders, keep the bugs out, and keep the cat in. However, it's hard not to feel a bit betrayed when you hear that clearly audible click as the door shuts...locked... with your keys inside.
It's actually quite strange, the behaviors that humans go through under situations like this, where we've locked ourselves out of our home or car. Most of our actions actually appear to run contrary to what we know in our brains. You know for a certainty that the door is indeed locked, and yet you still reach out and try to turn the knob, often repeatedly. This is typically accompanied by reaching, again repeatedly, into pockets, as if the keys will somehow magically appear there if searched for enough times. Of course, the unstoppable need to actually set eyes on the keys will eventually overwhelm you, leading to the performance of whatever gymnastics is needed to allow you to look through the window and see the keys, likely lying wherever you left them.