All of what you guys said + hats.

At my gym there are a few kids who will come in sagged jeans showing their boxers, tight fitting shirts and a baseball hat on backwards, sideways, crooked and leaning forward, whatever.

These are usually the kids who weigh about 150lbs and walk around as if they own the gym. This is not a fashion show, this is the gym. I've been tempted on more than one occasion to give em a swift kick in the head