Not "overheard", but "saw" at work, but this is my favorite.
On nice days, I'll spend my lunch sitting in my car (not idling of course, windows open) - reading, people watching, etc. One day I saw two people return from their lunch, walk halfway back to the building, at which point the one woman noticed an open parking spot closer to the building, so she walked back to her car to move it to the closer parking spot. OMG ;-) Never mind that she had already walked the difference between the two parking spots, so she wasn't even saving any walking (not that that's an excuse anyway). This was several years ago, but I still laugh about it...