Matt Mower turned up an entertaining Aristotle quote from David Gurteen's knowledge quotations mailing:
"It is easy to perform a good action, but not easy to acquire a settled habit of performing such actions."
*** Aristotle (384 BC-322 BC) Greek Philosopher ***
On the other hand the first step into a new habit is to take the action. With respect to personal effectiveness, this is a beautiful quote. It is difficult to form the habit, as I have discovered over and over. But I have to at least act like the good thing is already a habit, even if it isn't.