These are things which happened to me whilst I was in retail (never makeup but retail nonetheless)
I used to work in La Senza and an old man once came in and saw a girl who worked there bend over (her thong was on show) and he popped a boner right there, it was mighty disturbing.
I also used to work in H and M and people are nasty, I used to work the dreaded Saturday morning aka the morning after shift, you wouldn't believe how many people would come in with clothes they had clearly worn the night before wanting a refund, adamant that foundation only rubbed off when they tried it on, that the outfit was always cream around the pits and in many cases, the skirt/trousers already smelt like wee. In the end we took to wearing gloves when dealing with refunds because people were ridiculous. This one girl returned the pair of stilettos which were had blood and crust in the toe part and she went mad when we wouldn't give her the money back.
My first ever job was in Sainsbury's which is a supermarket. The nastiness of people knows no ends, I used to see people using the roll on deodrants, lipbalms, hairsprays and gels etc..HORRIBLE! Once this man farted really loud by my section and it stank so bad I had to run out to the bad and I yakked up.