Carding people who are obviously not under 21
Whether you’re heading into a bar or buying a six-pack at the grocery store, there’s a good chance you’ll be asked for your ID in the United States—even if you’re well into your 50s. This is baffling to many foreigners, especially since, by the time they’re in their 30s, they’ve been drinking legally for more than two decades.
Americans are nothing if not by the book about the little things, so most foreigners quickly learn that it’s wise to keep some form of ID on them at all times if they plan on having a drink.