Why do most people have trouble making exercise a regular habit? There are probably a number of reasons, but here are the main ones as I see it:

Too difficult
People set out with a lot of ambition and enthusiasm, and start out with a goal. The problem is that the goal is often too difficult to sustain for very long without some kind of structure and support system in place.

Too many goals
Often we set out to do too much. We want to eat healthy, quit chocolate, and stop drinking alcohol. Well, those are multiple goals, and most people find it too challenging to focus on the exercise habit if they’re trying to do all the others at the same time.

Not enough motivation
It can take great discipline to achieve a healthier and fitter body. Having someone motivate you can be an invaluable asset if you want to see out your goal.