When we recently went to the USA it was interesting to compare the standards of customer service in bars, restaurants etc in Massachusetts (Boston and Provincetown) with the ones in the UK. A very sociable American staying at the same guest house as us thought that the fact that staff in the USA are low paid and rely on tips means they've developed a more definite "service culture", leading to better service.
I'm not sure about this. Certainly the service we got in the USA was in general more attentive, but I'm not sure that it was much more polite or, overall, any better. Yes, it's nice to be asked "How are you today?" when you arrive, but we never quite believed the asker was interested in the answer.
In one establishment we stood at the counter for about three minutes while the person behind it carried on making some sandwiches, looking up at us occasionally but not acknowledging our presence. Finally she came and said "Hello. How are you today?" as if we had just that second arrived! On another occasion, I was amused by the waitress who served us water from a jug pouring lots of it down the front of her own apron on every occasion and appearing not to even notice. She was very polite but, unfortunately, disappeared completely after leaving us the bill. When about twenty minutes had passed with no-one near to service us, we had to go and find another member of staff to pay. Ironically, our friend from the guest house told us a story of the amazing rudeness he had experienced in a restaurant in Provincetown, so obviously the higher service standards he talked about are not universal. Overall, it seems to me that service in this part of the USA is just as variable as it is back at home.