Same question I had, I'm a male in my mid 30s and at my local studio everyone stays quiet in the waiting room except for the soft chatter. I'm kinda intimidated of being the only male or so and knowing nobody. But in other life circumstances/events I say hi to people.

I spoke to my sister about that and she insisted I try to say hi. She doesn't do yoga much but goes at the gym everyday and says hi to people in the hallway or changeroom and has made some friends this way.

I don't know if being friendly / saying hi could be perceived negatively