And that also applies to the GYM environment.
Some things should be avoided at all costs. They are not only dangerous but can hurt you badly:
-Heavy weights. The mentality that the heavier more muscle is not correct. What develops strength and size is a good diet combined with exercise and rest periods.
-Group classes. To add a few people in a dark room (that is dangerous by itself), with no assessment of anyone's health, history and so on, is like going to a doctor that examines people by the dozen. One on one training is the only way to train properly.
-Drinking stations and exercise mats. I would avoid those due to hygiene reasons.
Not everything is good for you.