[anthomtb]

I would say this is a difference between a short-term habit (going to the gym) and a long-term goal (being fit). Habits can be long term of course, but likely to fade if they don't resolve around some long term goal.

If your goal is fitness and the gym isn't interesting, you will find some other way to obtain fitness. Maybe martial arts, maybe a physical team sport, maybe an individual sport. Then at some point you'll plateau at your sport, or the offseason hits, or you need more strength or endurance, and there's your reason to get back in the gym. Rinse and repeat for as long as you want to stay fit.

[borroka]

Side note, but most people who say they don't like lifting weights have never lifted weights "properly" (most personal trainers are not good teachers of either technique or intensity; it is a profession with a low barrier to entry) and have never seen the visible effects of lifting weights on their bodies.

It's hard to say "I don't like lifting weights" when people start complimenting your body and looking at your biceps, pecs, glutes, etc.