I have noticed that here in the DR, when you tip, very often you don't get a 'thank you.' I just wonder why that is. In our casino, we literally had to train the staff to say 'thank you' when getting a tip. I noticed it again on the tennis court, I tip the ball boy RD$100 after a game, which should be considered a good tip, but he just doesn't get the word 'gracias' or 'thank you' out of his mouth. I have lived here 7 years and I just don't get it.