This post prompted the following response, which I was going to post as a comment until I realized that it had become a blog post.
I think that what we understand 'cool' to be changes as we get older. I used to think extreme hair was cool until I met an asshole with extreme hair (who wouldn't talk to us because we didn't look cool, apparently) and a wiser friend said, "it's sad when someone's entire personality is their hair." I also used to think that people who went to things like Burning Man were cool, until I realized that attending an event does not make someone cool and that lots of people go to this kind of thing in the hopes that it will make them cool.
Most of the time, 'cool' seems to be about external things - hair, clothes, the kind of music someone listens to, maybe the kind of job someone has, etc. At the ripe age of 42, I've realized that cool, for me, is more about what someone *thinks* and what kind of person they are than what they look like and what they do. Of course, these things are more abstract and are not attached to specific acts or looks of 'coolness,' like smoking a cigarette or wearing black. But it makes sense that coolness should be abstract - it should be something you have to look for, something that you need to patiently discover in unusual places, rather than something you can buy at the mall, see at Burning Man, or find on Facebook or on television.