Oh man, I read this and get a sinking pit in my stomach. I don't care about a person's color, reproductive organs, creed or whatever, but I wonder if perhaps I care a little too much about their "similar thought process", "go out for a drink"-ness (gulp, and what does that say about age), and most nebulously, "comfort". I thankfully cannot think of a time when I turned away a candidate for any reason but pure technical skill, but one look around my current office shows a pretty age- and "cool"- homogeneous group.

Where is that line?

Looking at something dumb, like TDD. Is it okay to hire someone who doesn't "believe in TDD" when the rest of us practice strict TDD? Somehow, almost certainly based on nurture of past jobs/mentors/failures (we all like to think it is nature, pfft) all developers look at the same facts of TDD, and yet some are on this side, some are on that side. TDD is an arbitrary bar. May as well be favorite color. But, when the house painting team is 15 guys who like red and so we only paint red houses, but you like blue... Maybe they just are not a good "cultural fit". Shrug. Would that one blue person "poison" the team? On the one hand, that blue person might open us up to new opportunities, get us to start doing both kinds of houses. Maybe they just end up fighting with everyone all the time, "CAN'T YOU SEE RED IS THE BEST WHAT IS WRONG WITH YOU?!" And so cultural fit seems like a way of saying, "people similar enough to our average skill to not make anyone mad, and similar enough to an average of our shared backstory so as to have basically the same conclusions about the Big Issues as we do: TDD, FP/OO, Pairing, NoSQL/SQL, IDE/Editor, languages, what goes on the Big Issues list, etc.

But in all that, aren't we really just saying, "I want to hang out with people like me"?