these have certainly kept me laughing!! Used to work in a famous high street jewellers, and often had dodgy customers, the manager was (and still is) the biggest odd ball of all, he'd allow snot to drip onto the counter like rain drops or a river instead of wiping his nose, we once had an old lady and a dog in, when the manager was moaning (to the dog) the dog wee'd in the store, the manager confronted the women who denied her dog would ever do it!!!
Didn't have too many things left behind, but I was naughty once (forgive me for I have sinned) someone left a video (Convoy) behind and it was from the library, instead of taking it back for him.... I kept it and gave it to my brother who's a trucker for Xmas!! (I was a student!) oh the joys!!