I'd argue it's a game of chance. You already mentioned a lot of things necessary to "build" a friendship, but I dislike the word "building". While there certain

I'd argue it's a game of chance. You already mentioned a lot of things necessary to "build" a friendship, but I dislike the word "building". While there certainly are mistakes you can do, friendships are usually not "build" - maybe some work needs to be put in to be "maintained" in the long run. Genuine friendship comes with shared interests (which is why it's easier to find friends in common activities that you are genuinely interested in), but also the simple chance of meeting interesting people. The best predictor of friendships in student dorms seems to be the relative distance of their rooms - see Kurzgesagt's "Why You Are Lonely and How to Make Friends" at https://youtu.be/I9hJ_Rux9y0 https://youtu.be/I9hJ_Rux9y0 for some more interesting facts. It's completely normal to have different level of friends - some to party with, some to nerd around certain topics with, some to have deep meaningful talks but you only can stand a meeting once a quarter... And you are only able to actively maintain a certain number of friendships. I found that I don't have nearly as many "friends" as many of my peers have (being a 40-something doesn't help much either), but the friends I got are rock solid. They are kinda lopsided because I'm offering too much help most of the time without accepting much help from them - that's what I need to work on.