Most users on /r/AskAnAmerican don't seem to consider American friendliness fake:

https://old.reddit.com/r/AskAnAmerican/comments/ehe25w/why_a...

https://old.reddit.com/r/AskAnAmerican/comments/1k7sfbv/so_w...

https://old.reddit.com/r/AskAnAmerican/comments/1nq71lc/why_...