Things to say no to:
1. Cookies. And cake. At least on a regular basis.
2. Answering the phone when I KNOW it's a telemarketer.
3. The time-suck known as Plants Vs. Zombies. Or Angry Birds. Or Spider solitaire.
4. Running faster than I should at the start. Because I will feel crummy at the end.
5. Clicking on "just one more" link. Or blog.