Well, in the adult world, you hire mature, professional people who learn to work with each other and overcome their differences. It's fine if they aren't all buddies outside of work. In the startup "Real World" (a la MTV), you artificially craft a group of people who seem to "mesh" and then suffer the consequences later when the latent adolescent dynamics emerge.
I remember interviewing at a certain prominent software agency. I won't say who they are, but will only say that you've probably heard of them. Things went great, as far as I could see. I represented myself as someone who was technically competent and could get the job done. Great, right? They ended up passing and not taking me on. It took me a long time to extract the reasons why, but eventually they revealed that it was because of a perceived "culture issue."
Startup geeks don't seem to realize how frustrating an experience like this is. You go in, having done all your homework, having all the right experience, then you're turned down over something that you have absolutely no control. Something that is completely un-actionable and basically equates to saying "we just don't like you."
This cannot and should not be the way that people conduct business in the tech world.