I like the idea of Cross-Fit, push, pull, lift and they mix it up to shock your system. Again though, as you indicate, the group can push people to hurt themselves.

I don’t work-out in groups. It’s nice to have a training partner who is there to assist you (and vice versa) to avoid injury (check form, spot when going HEAVY), but I really don’t want a bunch of cheerleaders telling me to push my limits and then saying “sucks to be you” after the damage is done.

Everybody has limits and you’ve got to know yours. Pushing those limits incrementally is how you progress; pushing them too much can be dangerous. Start slowly and learn where those red-lines are.