A guy on a Locksmithing forum I use has a story about accompanying his Dad on a job, and parking their work can in a parking lot. Part way through, his Dad sent him to get the van and collect some part of tool from their shop.
He walked to the van, drove to the shop, slung the bits into the passenger seat, and drove the van back to the parking lot... Past The van he should have taken, which was still parked a few spaces further from the job!
He'd taken a van of the same make and model, keys had worked the door and ignition, and he never noticed a ring till he drove past a familiar looking registration!