That was a really insightful post by the thread starter.
I'd like to say that my gym has a good balance between hardcore and mainstream, which is interesting because I've never seen or been in a 'hybrid' before. There's definitely at least 3 obvious competing amateur bodybuilders that I can pick out, as well as a amateur fitness competitor. I've noticed only 1 potential powerlifter, but he generally comes late at night since he uses a lot of weight and time. There's also this huge, masculine looking lady who looks like she could have been a female bodybuilder earlier in her prime, maybe back in the 80's or so since she's probably in her late 50's. I suppose the rest of the people there are more or less average, but definitely in better shape than a Joe Schmo on the street.
Then there's the guys that come in and yack with each other as they all cycle off on bench presses for over an hour, as well as the tardish with a fannypack and clown pants. There's also one of the strange 'alternative' workout guys who spends the beginning of each of his routines by hanging upside down from a pull-up bar for at least a couple of minutes after slapping on his obnoxious weightlifting shoes and rolling up his sleeves

.
There's also a mix of trainers who clearly know what's up and those that are your typical jack off trainer. One guy in particular looks like he barely lifts weights, and everytime I see him, to quote Mike Mentzer's moustache, is always "fraternizing" with his own clients, who all 'happen' to be female

. He's probably the least serious trainer I've ever had the displeasure of seeing in action.
Maybe I'm used to it, but I'm able to clear my head pretty well and focus on my sets. I guess all I need is a few people that are obviously really into their training and have the mass and cuts to show for it, and it makes ignoring other people much easier. It seems like that's how the other focused people are also. There might be some sort of unspoken acknowledgement between all of us since we give each other space and the occasional nod. I don't really talk to anyone there. I go in, do my lifts, and rush out of there so I can hurry home to my post workout shake and whitebread slices.