How hard do you have to work to make something happen?
It's so easy to just let things slip. That extra pound doesn't really matter. It's not going to kill me to not practice today. I'm too tired to make that call.
Of course, you'll end up working hard at something. You'll make some activity, goal (or lack thereof), priority, or lifestyle what you choose, whether you choose it consciously or not.
Wouldn't you rather have the choice?