In my retail days I was always good at avoiding customers on my way out. Typically I'd take of my topshirt and just have my undershirt on as way of letting people know not to bug me when I'm off the clock, especially if I had my own shopping to do after the fact.
What used to piss me off is when you're closing and people are still in the store. Now I can understand some people have crazy schedules and might not be able to shop in the middle of the day, but show some goddamn respect for the person who put in an eight-hour shift and has to wait on your ass to finish checking out.
I'm sure you'll get a kick out of this story... one night when I was working grocery, it was almost midnight and closing time so I give the standard "store is closing soon, please bring your shit up front" announcement. Most all the customers come up to check out and everything seems to be fine until we do the store walk and find an older woman and middle-age woman (probably mom-daughter pair). We figure we'll let them get away for a minute or so to finish up... 12:10, still nothing, so I get on the PA and make a "the store is closed, please bring your shit up front" announcement. 12:20, we go peruse the aisles and find them still shopping, so I make another announcement, this one very emphatic. 12:30, they finally come up to the checkout and we find out why they didn't respond: Because they didn't fucking speak Inglés.