I'm already familiar with the GameStop experience. You go in, know which game you want, and the employees there expend all their effort to get you to spend a little more on impulse. They ask if you want the strategy guide (Hey, it's 10% off since you're buying the game!) or if you want to preorder anything (Heard about the new Call of Duty yet? Better reserve it now!) or if you want a special collectors' edition (It comes with a tiny art book!). As annoying as it is to have to go through a five-minute ritual of saying "No, thank you" over and over to the cashier every time I walk in, it must be good business. However, GameStop's incredible focus on getting customers to pre-order games has slowly gotten to an extreme level I can't really tolerate.
I remember years ago realizing that the cashiers seemed to always say I was getting "the last copy" of any relatively new game I bought at a GameStop. If I asked for Modern Warfare 2 a week or two after release, they'd search their drawers for five minutes before finally coming up with "their last copy." Given that the game shipped more copies than any other entertainment product that year, I found it a little bit surprising that they would actually be at a shortage, no matter how many they sold. It would have been almost impossible to stock too many copies of Modern Warfare 2; all of them would eventually sell. Anyway, this kept happening, over and over. "Did you preorder? No, well, let's see if we've actually got any copies left..."
The whole "last copy" thing was clearly a strategy to get me to preorder newer titles. They wanted preorders more than new game purchases partially because not all preorders are actually picked up from the store (like a slightly less effective gift card syndrome) but mostly because they want preorders to force impulse game purchases over thought-out ones. I was coming into the store because I knew exactly what I wanted, but they wanted customers to come out of the store having spent more than they planned, by preordering upcoming titles, making purchases for their future selves that they might or might not have made otherwise.