I bet you brush your teeth. But why?
Is it to make them look good? Or is it to avoid having them rot away?
People brush their teeth to prevent problems in the future. It takes years to get a child to understand that if he or she doesn't take care of his teeth, they're going to rot and fall out.
So why don't you have the same relationship with your body? People exercise to look good, not for future health. You can look around and know that as you age, your body will begin to break down. First you lose the ability to jump and run. Then your balance gets weaker. Then you become prone to injuries.
Young adults have a "normal" posture, and "normal" walking gait. But middle-aged people begin to show a "side to side," penguin waddle. Seniors are more bent over, and take smaller steps. Like oral hygiene, the body can be cared-for in a way that makes it useful for a lifetime.
Back to TommyTheory: "You can only exercise to the level you understand." So for many, jogging and weight-lifting are what they understand. This kind of exercise is beneficial when you're 25, not when you're 45. Others find out for themselves that energy practice is a boon to the body, and for sooth-- The Fountain of Youth. Fu Tai Chi and QiGong are special exercise that will keep you healthy and mobile your whole life.
Brushing your teeth is like a health bank; every day you contribute a few minutes of time so that when you're old, you still have your natural teeth. Fu Tai Chi is exactly the same; 20 minutes each day will extend your mobility much longer than if you don't exercise or if you jog, lift weights, or do most other forms of exercise.
The next time you brush you teeth, take a good look at your body and ask yourself, "Why don't I take better care of my body ?"