This makes a couple good points at once. First, it's not the exceptions and anomalies that are you. It's not that one piece of chocolate cake, or the one day you don't get your treadmill time in, or even the one time you are late to the office. It is what you do as a habitude.
Secondly, what you repeatedly do is usually up to you; which is both a freedom and a responsibility. As the apostle Paul famously points out, "That which I would do, I do not... wretched man that I am."
Some of the greatest things are very simple in the end (in fact, a lot of them are). I came across this stunningly practical site ("Habitforge" above) recently and hope you'll think it is too. The only caveat I would make is that when you break a habit, it needs a good replacement in order to make a lasting change. And since this is a free site, that doesn't cost anything extra.
* - A giant note of thanks to all of you who have downloaded the free PDF of the book summary from the TechRepublic site. It just went over 5,000 downloads last week.