Then maybe its a sheer lack of focus? No one telling them what to do or how to accomplish things. They go to the gym, simply to say they go to the gym, and when they get there, they are lost. THey work with the "I train what i feel like" methodology, which is always Chest, Biceps, running, or a combination of the 3.
People who are in the gym and "are just trying to improve themselves a little" still just dont know how to go about it IMHO.
If we are talking about people who just dont go to the gym, well that's their choice. The same reason i cant stand reading, but can spend hours on a video game. Preferences.