I suppose this depends on where you're coming from. My Eastern European relatives thought that Americans were oddly friendly. I remember my mother saying "Why did the cashier smile at me? She doesn't know me!"
A French coworker of mine back in Australia was talking about how much cashiers smile, and I was like "oh yeah, people are real friendly, great right?" To which she replied "I just want to tell them stop it, you're not my friend!"
Lol I'm like the exact opposite, if someone isn't smiling at me I'm thinking "Did I do something wrong?" but of course I know that not everyone is smiling at you unfortunately