About 5 years ago, I left my credit card at a restaurant in Key West as we were leaving town. We run 2 credit cards, so it was easy, but scary, to cancel the one I left. (Of course I've done that in town, but it is so easy to go back to get it that it's now worth telling.)
A year ago last spring, I had been to the doctor 25 miles away, got some bad news, went to McDonald's to calm down with a breakfast burrito (or 2), locked my keys in the car. So I called my husband and he grabbed his keys to come help. He got there, and it turned out he had grabbed the motorhome keys, not my extra set for the car I was driving.
About 6 years ago, we were on the ferry to Vancouver Island and parked our tiny motorhome right next to the of the wall, so I had to get out of the driver's door - that is pretty hard, not just scootching across a seat. For some peculiar reason, my husband left his keys in the ignition, and I, who always make it a habit to carry an extra set in my pocket, had thrown mine on the floor in all my maneuvers to get out of the driver's door, and then out of habit slapped the doorlock while shutting the door. Security didn't seem too upset, but we did miss about half of that lovely ride in the bowels of the ferry watching them try to unlock our vehicle instead of in the observation lounge.