I have a few from my mis-spent youth spent working in a series of low-end shops. 1) never buy the cheese from a deli counter-the dates are dubious as is the hygiene of the teenager serving you. 2) the cleaning and food management in a supermarket is largely superficial-I would regularly find food which had gone out of date weeks if not months before. Once I found raisins that were 3 years OOD!
3) the sale stuff at JD Sports was brought out from god knows where and was all from years before.
4) never buy food from a sports stadium. We had a mouse issue and no one had food hygiene training
5) be nice to staff in shops. None of us were dense but were often treated like we were at best stupid, at worst, second class citizens.
I no longer work in retail! N.b these were all in the late 90's-early 2000's so hopefully the training for these jobs goes beyond 'get on with it' 