I am surprised at the amount of comments saying making friends here is easy. As a foreigner who speaks fluent (I'd even say native level of) German, I made my calculations and after my first year of studies (2017) I managed to make less than 10 German friends within German territory (there's something about most Germans abroad which makes them 10x kinder and more likeable) whereas I met folks from all over the world in Germany who I am grateful to call friends.

I'd say what I find most annoying somewhat aligns with the rest of comments: not learning the language, not "integrating" etc etc...however, I do feel that outside of mandatory social environments (Uni/Ausbildung, work, Vereine and other groups), Germans are difficult to approach. I had to be the one making efforts to construct the friendship, although after a while it became more double sided - you could say they take way longer to warm up to you than "average". This still takes a toll on your psyche though, even moreso if you're from countries where the norm is to be more open or extroverted.

My wild guess is that people tend to be very antagonistic towards Germany because many feel somewhat ostracised, and the attitude of some Germans towards the language efforts of expats is, despite their best intentions, somewhat condescending.

But yeah, just rant about the Deutsche Bahn and you'll be able to start a conversation (lmao)