There is a lot of conflicting text in the main thread. The title talks about mediocre vs intelligent and the text speaks of cordial friends vs critical ones. Exactly what is this discussion about? If it is the first one, I would say that are you going to set parameters about how your friend is? How would you define "mediocre" and "intelligent" in the first place? A person who has nothing much to say and you have one-sided conversations may be considered mediocre but you would not necessarily shun such a friendship. A person who has a finger on the current happenings and converses in a smart way may be considered intelligent and great to have a friendship with, but when it matters most and this so-called intelligent person is not there to support you, what kind of friendship would it be?
Same with being cordial and critical - how do you set these as a base for friendships? Would you stay away from a friend who is bold enough to tell you what is what and stay with one who only pampers and flatters you?
It is hard, really, to say why one develops a friendship. It may not even start with a common interest in something. It may start with just a simple hello, sitting next to each other on a bus and an immediate liking for each other. This is just an interaction. The friendship comes later, when you meet, talk some more, make tentative steps into knowing each other and when trust and mutual understanding sets in, then the friendship can blossom. So make a friendship without expectations and accept a friend with no adjectives. Then only you can cherish it, perhaps it being a lifelong one.
When you make a commitment, you create hope. When you keep a commitment you create trust! ~ John C. Maxwell