@papa

I think it has more to do with the fact that in American Society we are accustomed to tipping 15 to 20% at bars an restaurants and we tend to bring that with us to the island. It's not the case everywhere else in the world, and they bring what they are used to with them. If a bartender knows he is going to get a good tip with fast service he is going to get to you first, and that's the way it works in the states as well. If you are tipping every round of drinks, you wont be waiting long at the bar. If not... well...