Have you ever tried a board game meet up? I mean, if you like board games at all. Then there's no pressure to start a conversation outside of the game, although it could happen. I would go back to my local one if there wasn't pressure for a time commitment and if I felt that I personally could create deeper friendships/had more time, but they're more effective for people who struggle with starting conversation in my opinion.

As for talking to random people on the street, on the bus, etc., I've noticed (and it could just be where I live) that people will randomly strike up a conversation with me solely because I'm carrying an instrument or because my hair is uniquely colored. It just seems that if you want random people to talk to you, you have to look interesting enough.

The only times I've been able to develop anything deeper than random people coming up to me was through school, a greek organization I belong to (except I don't really fit in anymore), and through work as a gigging musician. You play a gig and you drink/eat together, that sort of thing. I really don't know how people bond enough to have friends, let alone best friends (unless it's a romantic relationship and chemistry helped that along). Hopefully someone here can explain it for both of our sakes.