I climb because I (for the most part) have a very strong dislike for people and love being outside so rock climbing facilitates my needs well. I've never been to a gym, can't understand the reason for going to the gym. I honestly don't understand at all. It's like paying to lift weights, pointless and unproductive. I think there's a rock gym 3 minutes from my house and I have no clue where the place is and wouldn't go if it was free.
So the things I hate most about the gym is it's unnatural, there are far too many humans there, it's inside, I'm guessing it stinks, the idea of dirty holds freaks me out, it's too controlled and it involves nothing I see as a reason to rock climb.
The fact that they use the YDS to rate the climbs at all.
From the ASCA:
The use of outdoor rating systems in gyms is inappropriate and leads to safety issues
Modern climbers learning in a gym are often misled by the use of the YDS in indoor gyms. The use of the YDS inside is entirely inappropriate, as indoor gyms have little relation to outdoor climbing. Most people who learn in a gym and think they "climb 5.11" would likely DIE attempting a 5.0 chimney system first climbed in the 1930s. Because of this new generation of gym-educated climbers, the use of the lower 5th class ratings has fallen by the wayside, and modern climbing guidebooks typically condense all climbs formerly 5.0-5.6 into the 5.6 rating. A large number of accidents are directly attributable to the use of the YDS in climbing gyms.
Gyms suck all around! If I cant climb outside, I dont want to climb indoors because its a gym and there is always a bunch of gumby idiots, bad music and horribly set routes that makes me wish I would have just went straight to the bar and spent my day pass fees on an extra couple of beers! If you dont live anywhere near real rock, I can see enjoying a gym...but to someone that lives 30 minutes from over 2000 boulder routes and hundreds of roped routes, its like masturbating to a porn while a hot chick is naked, ready and willing right in front of you!!!
The dude that runs it is kinda mean. He doesn't seem to like people. And then also, I would climb outside, but I don't know who to climb with.. And plus, the nearest place to climb is like 45+ minutes away.