I live in a campo beach town outside of San Cristobal and most of the people here are very poor. One on one I find them amazingly polite, but they are oblivious to some things. Like blocking the road with motorbikes or standing in the road to talk and expecting the cars to just stop and wait (Mr AE is not amused by either). When he was sick with dengue, many came to the gate to ask how he was doing.
i shop mostly at La Sirena in San Cristobal, and have never experienced anything like rudeness from the other shoppers. If someone is blocking an aisle I wait a bit and always get an apology.
Now Mr AE, maybe from living in the US for 40 years, always says please and thank you there. But here in DR it's like a switch has been flipped. He will pull into a gas station, for example, ask directions , get an answer, close the window and drive away. No thank you to the guy. Yeah, I say something, and he shrugs. In many ways, he's different here.
My inlaws don't speak any English, but they do know "thank you" and use it with me.