I'm an occasional victim of the "ohnosecond" - that infinitesimal slice of time where you realize you've done something dumb but it's too late to stop yourself.
Most recently I was hauling a huge armload of stuff out to my car and as I struggled to click the unlock button on my keyfob, open the door with one finger, and ease the pile onto the seat, my keys fell to the floor of the car. Then my elbow bumped the lock button on the door, locking all the doors of the car. As I shoved the door shut, I had the "ohnosecond" and tried to grab it before it slammed home, but it was no use. My car doors were all locked, my handbag (and phone) inside, and my spare key was locked inside my house. To make matters worse, my external garage door opener's battery was dead.
I knocked on the doors of all the neighbors I know, but none were home, as it was in the middle of the day on a weekday. Thankfully a woman soon appeared with her dog and I was going to ask her to call a pop-a-lock place for me, but she instead let me come to her home around the corner where she loaned me a 9V battery which allowed me back into the house. I got my keys and returned the neighbor's battery (and I have since replaced the one in the external door opener) but I was about fifteen minutes late for my engagement. That'll teach me. I should have picked up the keys as soon as I had put everything else down.