Why Do You Train?

It's easier to stay on the couch. It's easier to eat whatever you want. It's easier to allow your muscles to atrophy and your health to fade away.
It doesn't happen overnight, so there will be no sensation of it happening. Besides you'll be enjoying all the pleasure that can be had from zero activity and supersized meals. You don't need a lot of strength to lift a remote or get a cheeseburger to your mouth.
Enjoy it. Life is too short.

Exactly.
Life is too short for me to try shortening it even more by clogging up my arteries, weakening my immune system, and having a hard time just moving around.
I train to be stronger (muscle mass assists with longevity. And strength is cool).
I train to be fitter (so I can play WITH my kids).
I eat to be healthy (so I can be around to play with my kids' kids).
And I train simply for the joy that comes from achieving goals and self-improvement.

It's about what you want out of tomorrow.
Do you want to accomplish something or simply watch your measure of life slowly drip away...