Great concept!

Just as important as the things you want to do, are the things you really shouldn't be doing - like your bad habits.

This would be a great way to keep track of all those little things, which when added together, can lead to you wasting time, being unhealthy, self-destructive/defeating...the list goes on.

And just be listing your 'not to do's', you're bringing them to your attention - which, I suppose, is the first step of the battle.

This is something I'll be looking at myself (and is kinda connected to an idea I've already had/been working on).

Great hunting :)