Anyway, was struck me about CrossFit and really any group exercise routine is how much more it makes you tax your own body. When you're at the gym, you don't push yourself. You run comfortably fast on the treadmill, lift a comfortable amount of weight, and do it at a comfortable pace. Group exercise is great for breaking you out of that habit and making you push your limits. It's too easy to pretend that 45 minutes at the gym, 15 of which is "cardio" and 15 of which is "cooldown", is going to change anything.