There's a bit of a myth that it is against coffee culture. Just like you don't get coffee to go, because you are in a rush, and therefore won't be able to enjoy it. If you are ordering two shots at a time you are also not relaxed, and won't enjoy the coffee.

If I'm tired and jet lagged, I do it all the time. It's not called espresso, or double espresso. If you want it natural, meaning no foam, cinnamon, or anything else, you ask for caffe' doppio. That means double coffee. If I'm in a rush I'll ask the bartender for doppio macchiato. The bartender often looks unsure at me and says, "doppio?" And I say yes, doppio, and he makes it after a shoulder shrug, as if he has a little doubt.

Coffee in Italy is not called espresso. It's just called coffee. All coffee in restaurants is made by passing pressurized, steaming hot water through the grinds. An espresso machine can make a perfect cup of coffee in 20 seconds. Its called caffe' because that's what you drink. You don't drink the espresso machine that made the coffee, you order the coffee it made.