If there’s something else that a retail associate does besides sell, it’s clean, fold, and upkeep the store. Customers need to look at clothes, that’s the nature of the business, but you should remember that every item you unfold—someone else will have to refold. Employees should do their job, however the employees are there to help you. Need a medium? Ask the guy or girl that works there—that’s their job.
There’s no need to unfold the same shirt in twelve different colors, and then proceed to throw them in a big pile on the table, across the store, or in something that resembles your laundry basket in the corner of the fitting room. It’s a simple courtesy. While being a clean shopper isn't going to get you props off the bat, if you make a wreck of the store, associates will count the seconds until you leave.