I couldn't come up with 10 at the moment, so I'll start out with these five general rules of retail, and probably add more later.
1. Somebody will always come in 5 minutes before you close, especially when you have somewhere important to go after work. I even had someone call and after finding out that we close at 9, inform me they would be in at 8:50 because that's when the bus schedule worked out for them. At least this time I had fair warning.
2. Don't go in to work on your day off. Once I had to stop in for a memory card or something stupid, and it turned into 45 minutes of answering questions about the 360 for customers and digging through inventory for one lost movie. And the fun part? You don't get paid for that time.
3. Don't hold up the line trying to find exact change at the register. Seriously consumers, I know you get warm and fuzzies thinking your 37 cents will save me from having to give you change, but we're well equipped to handle payments that are over the invoiced amount. In the four minutes it took you to dig through the purse, count the change, drop the penny, chase the penny across the floor, pick up the penny, then recount all over, I lost a customer who got tired of waiting.
4. Don't leave ANYTHING lying around the store that doesn't belong. The reason for this is the "small child from hell" will pick it up and cause trouble. We have metal doorstops near the front door for nice days, and during one busy session I remember looking up to see a monster kid running around with it and poking at his brother. The mental picutre of a metal doorstop stuck in some kid's eye socket flashed before me, so I grabbed it and hid it behind the counter.
5. Be ready for stupid, general technical questions that have nothing to do with your store. One guy called me, said he bought a game online and it's not working for him. He then went on to explain that it says PAL on the cover, and what's that mean? I said it was the European version of the game, and started to look up our Amazon records to find out how we sold a PAL game through our Amazon business. He then said he bought it on ebay. So......rather then contact......I dunno.......the SELLER of the item, why not try a game store to figure out your problem. Or just ask the guy pumping your gas. How about writing a letter to the president of the United States? He can help.....