If evolution is true, then why hasn't hair evolved?

Yeah! What an odd thought? Are you angry with someone? Hmm that's bad. Specialized cells have their own task. If a cell is meant for hair, thus it grows and become hair. So as species. You did born as a lizard, then evolved into ape, then fish, then man, then whatsoever until the end of your life. Huh! That's odd.