One difference I noticed in Europe, relative to the U.S., was in eating out. We didn't generally eat at fancy places but at brasseries, cafes, pizzerias, etc.; I think they were generally the same 'level' of eatery we mostly eat at here. What I noticed was that the waitstaff service was much, much slower than I'm used to.
Maybe one factor was a difference in attitude about dining, a more leisurely attitude. If you think of eating out with friends as a relaxed, multi-hour affair, you might not want the waiter imposing too much (although I'm straining to think of 'taking your order' or 'noticing that your glass is empty' as 'imposing'). I'm willing to chalk up some of the slow pace to cultural differences.
I wonder how much the tipping customs make a difference, though. Customers generally don't tip in Europe. I often don't like the custom of tipping in the U.S. because I think waitstaff should be paid decent wages without having to depend on the kindness of strangers. I've heard horror stories of snotty customers treating waitstaff poorly and unfairly. Perhaps I've overlooked a major advantage of the tipping system, though, which may be that it results in restaurant service that is much better than it would otherwise be. Of course,
I like to determine how much money my waiter receives for the level of service I got.
The worst service we got was at lunch in Paris, where the waiter all but ignored us, got
rebelzero's order wrong, never brought our drink orders despite a reminder when we managed to get a moment of his attention, and might never have brought the bill without the intervention of another waiter. Fuming, I thought to myself, "This guy has totally lost his tip," before I remembered I didn't having any tipping power here (except to reward exceptional service). Other customers at the restaurant seemed to be suffering from his lack of service, too, which brought to mind another possible factor: labor laws that—according to my understanding—make it more difficult for employers to fire staff than it would be in the U.S. I'm just speculating, of course. Your viewpoints are welcome!
Addendum: From the most recent J-List newsletter:
Japan is unique among industrialized nations in that the concept of tipping never caught on, and is in fact about as alien to people here as taking your shoes off before entering your house would be in the States. You can expect service with a smile wherever you eat (as a wise gaijin once observed, "in Japan, you know no one is horking in your food"), and if were to leave a tip on the table you can be pretty sure the staff would run after you to return the money to you. While it's certainly nice to not have to tip when eating out, there are times and I receive exceptionally good service and want to show my appreciation, but the lack of a custom of tipping makes this impossible—it would actually be quite rude to even try in most cases.