They're human beings with a job to do. Part of this is engaging with you, but different cultures treat the boundaries differently. In the US this involves small

They're human beings with a job to do. Part of this is engaging with you, but different cultures treat the boundaries differently. In the US this involves small talk and as it makes people happy I do it in situations where it is normal. Other countries think differently, it's cultural so there's no right or wrong here. Engaging someone with small talk where it's not expected is felt as rude as not doing it where it is, if that makes sense. As for the other point. I've seen Americans being polite, but I've also seen them belittling staff, shouting and being generally rude. I've also seen this from non-americans, but far less frequently. I assume this is selection bias (the American tourist syndrome - you only notice the loud obnoxious ones). This is across multiple countries.