I almost posted this under "Am I going mad?" Just been to the supermarket with my own carrier bags, including one of my favourite ones (because it's shallow/not deep saw me struggling and said - unobtainable in the UK!) Put the bags in a trolley, put the pound in to release trolley, trolley had gammy wheel, handsome older man about to leave his trolley in the trolley park area said "Here have this one for free". I was so delighted/distracted, promptly left all my bags in the first trolley - and they got nicked!
I can't 'fess up to my stupidity anywhere else ... :P