I'm American, and a immigrated to the US from India at a young age. Both cultures in my experience are very open to talking to people you meet in line or that you don't know at a bar, exchanging pleasantries, connecting with strangers, etc. Everything I've heard about Europe is the opposite, that people don't make small talk or smile at strangers.
I know this isn't universal, I have been to Scotland and Italy and people were more than happy to talk and have good conversation, but I have definitely noticed a more reserved culture in a lot of places like France and Norway. It makes me wonder, how do people go about making friends? Obviously talking to a stranger doesn't always lead to lasting meaningful friendships, but I have many friends that I did meet waiting in line, or leaving a movie. I met my best friend in line for coffee. Is this just not a thing in a lot of Europe?