As somebody with that attitude, it's because I find it quite zen just to relax and be groomed by a professional. I won't shut down conversation, but I won't initiate it either.

The other thing is that decades of motorcycling without ear plugs has rooted my hearing, so talking to people with thick accents (I'd say 50% of hairdressers here are immigrants) can't be tiring, which is the opposite of why I actually enjoy getting my hair cut. There's a nice Korean lady I sometimes see who chats away merrily, but I feel like an arsehole having to ask her to repeat herself the whole time.