I'll make this one short and sweet:
The time I lost my wallet while out of town several years ago, I was with several friends who would be driving back home along with me.
Earlier that day we had ransacked just about all of Lake George looking for it, then finally had to give up and drive back to Danbury.
After I'd finished notifying the bank and credit card companies that the cards were to be declared lost or stolen, I was still sitting at my desk, dazed, when my friend came in and sheepishly handed me the wallet. "Ummm.....is this the one we've been looking for?"
He'd accidentally picked it up and put it into his bags thinking it was one of his other items, and in all the retracing of steps and looking through things, he never dreamed of checking that part of his luggage.