I find a lot of friends in libraries. Here in D'dorf, we have an International English Library and I sit in the back room with a coffee and the latest journals and newspapers and before long, someone else there will strike up a chat, or I will.
I'm also a bit of an introvert and I go and do lots of VHS courses because at least there you are surrounded by people and chat a bit. Sometimes, I might go for a coffee with someone afterwards.
I have a German mother and visited the German grandparents every year when growing up, but I find I don't have many German friends.* Only one. Lots of acquaintances that I can chat with - mostly in my walking group. Nice people. But not friends really.
Most of my friends were made here but now live back in their home countries and I don't see them any more - or very, very rarely.
I think if you can call one, two or three people 'friends', you are doing very well. Otherwise, you have drinking buddies, evening class companions, the person you meet up for an ice-cream and a chinwag, the person you meet up with at the cinema for NT Live broadcasts and so on. But a friend to hang out with and spill your heart out to... difficult. And rare.
*Mind you, when I studied in Manchester, I had one English friend, and when I worked in London for 4 years, I had no English friends. I am doomed to only get on with complete foreigners it seems.