When you vet someone for whether you can be close friends with them, what's a seemingly unimpactful characteristic about someone that would instantly rule them out as a potential close friend for you?
Maybe you don't like the wording, but everyone does this. Unless you know if someone will be a close friend the moment you lay eyes on them, or are friends with literally everyone you've spent time with.
At least for me, there's never really any conscious stage of vetting people. It's just a long process of repeated interactions, and eventually some of them become friends and others don't. There's no grand registrar of friendship that I file people into for processing.