1. Leaving an enormous amount of clothing strewn around the floor of the dressing room — bonus points if they’re streaked with makeup! — and walking out as though nothing happened, not even trying to hand you their unwanted items.
2. Walking around the store and just sort of… putting something back on the shelf, about a half mile from where it’s supposed to go, in full view of an employee. (Why is just asking, “Hey, could you put this away for me?” at the very least not an option?)
3. Asking if they can “take something home and then call you with their credit card number.” ???
4. Asking to hold things for a week, and getting angry when the hold policy is no more than 24 hours.
5. Angrily informing an employee that “you have the item at the other store,” as though that is somehow going to make the item materialize in the next 10 seconds from sheer willpower.
6. Not believing an employee when they tell you in full certainty that they don’t have any more of a certain item in the back room. (Usually they are so adamant because they’ve already checked for one or more customers that day, and if you force them, they’re literally going to go in the back room, stare at the wall, and count to 10.)
7. Having everything short of a house party in a dressing room, despite being told clearly that your friends can’t go into the room with you.
8. Walking out onto the store floor and just kind of browsing around for a while wearing the clothes they’re currently trying on, barefoot and with tags sticking out everywhere.
9. Taking an item from the bottom of the stack, letting the entire stack topple over in front of them, and not even batting an eyelash.
10. Giving the “one-finger” sign to the cashier.
11. Getting in long, protracted arguments with the cashier about what “no refunds, exchange only” actually means, and why, no, we can’t rewrite the fundamentals of the company policy just so that you can get your 30 dollars back.
12. Blatantly attempting to return things that are beyond used and worn out.
13. Trying on an item that is clearly at least three sizes too small for them, and destroying the item in the process (and then leaving it on the floor, of course, because why not??).
14. Threatening to “call corporate” about a problem that the employee has no control over. Everyone should understand by the way that “calling corporate” is what every employee dreams a disgruntled customer will do, because it gets them out of your face and ensures that they will be sitting on hold for the next three hours.
15. Demanding to speak to the manager and, when informed that the person they’re yelling at is, in fact, the manager, not believing them.
16. Requesting giant bags and gift-wrapping for a three-ounce item that cost six dollars.
17. Trying on excessive amounts of clothing that they have no intention of buying strictly to take endless selfies in the dressing room. (Yes, the employees know when you’re taking selfies. Yes, they’re making fun of you.)
18. Cornering an employee to “ask them about something” which is basically a way to hit on them when they can’t escape.
19. Asking if they can get a “sample” of things that would never in any universe be considered samples.
20. Pitting the employees against each other by telling them that the “other one always does it” when one of them says that they can’t do something.
21. Ignoring signs that ask not to bring food — especially ice cream — into the store, and then dribbling ice cream down the front of several items.
22. Without asking, just leaving a giant cup of Starbucks at the front counter while they shop, until you have a little petting zoo of random Starbucks cups next to the cash register.
23. Generally talking to you as a retail employee like you are the temporary butler that they have personally hired, and not like you’re a representative of a company that has rules to abide by and a dozen other customers to be helping. You can always tell when someone doesn’t think retail is a “real job.” 
