Nothing. I don't notice people at the gym. Literally, I remember no faces, no people, no nothing. I've been in my new gym for a month now and I have 3-4 memories of the place, apart from remembering where all my favored training equipment are. I remember I saw one of the TV screens once. Saw a trainer standing next to a treadmill with someone. Saw one of those lights that flash when you're supposed to move to your next machine in circuit training. And I remember a poster against a wall advertising something or another.
It's so easy to ignore the weird, the fuck ups, the insane, the attention whores. They don't exist in my world.