I liked what Susan and Stephen had to say. A lot of people these days are so uptight and stressed out to the max that going to the gym just adds to it. Especially huge corporate gyms, I have a relative of mine who has an anxiety attack whenever I bring her into my gym. It’s big and full of the “beautiful people” most who are wearing sports bras, shorts and many guys are shirtless. This is very intimidating to the people who need to work out the most.
I also want to add that there is a control thing going on too. If I work out at home I can try out new things and move my body in ways that would draw too much attention at a public gym. I don’t want a time limit on a machine, and I don’t want to obey all the rules all the time. This sounds bad but I like to get creative, and I can’t always do that at a public gym.