My impression is that in the U.S. bad behavior is encouraged to a certain extent by restaurants "comping" this, that, and the other every time a diner whinges. Last time I was over I walked in an eatery (waiting for someone). I ordered a beer, the waitress apparently forgot it and several minutes later came over apologizing profusely and then gave it to me for free. I hadn't acutally been bothered at all up til that point. In Europe, they'd probably excuse themselves but you wouldn't get a freebie. We were at another place where one of the party had a relatively minor complaint about something. Bam! She gets a coupon for a discount meal to be used another time.
This comping mentality doesn't exist in Europe and yet still, diners dine, restaurants serve, life goes on. By engaging in a space race to satisfy every single complaint with free stuff, restaurants are only teaching diners to complain as much, and as loudly as possible.