Renowned Harvard Business School professor, Clay Christensesn shared a story (hat tip to Prakhar) while addressing the 2010 graduating class of HBS. Here's an excerpt:

We got to the British equivalent of the NCAA tourna- ment—and made it to the final four. It turned out the championship game was scheduled to be played on a Sunday. I had made a personal commitment to God at age 16 that I would never play ball on Sunday. So I went to the coach and explained my problem. He was incredulous. My teammates were, too, because I was the starting center. Every one of the guys on the team came to me and said, “You’ve got to play. Can’t you break the rule just this one time?” I’m a deeply religious man, so I went away and prayed about what I should do. I got a very clear feeling that I shouldn’t break my commitment—so I didn’t play in the championship game. 

Ludicrous as this story may seem, I can somewhat relate to what he is saying. I have a similar commitment, to myself. That I will watch every single competitive game the Chelsea Football Club plays. And I have kept this up for a good eight or nine years now.

About 6 months ago, I made another commitment to myself. That I will write a blog post every single day of the year. I kept it up for about 6 weeks. Then I missed one day, thinking 'just this once' and I can continue from the next day. But I only managed about 30 posts in the next 4 months. Nowhere near what my commitment demanded. I just didn't build that into my culture by allowing 'just this once' lapses now and then.

You can make any kind of commitment. In fact, millions of people across the world do it at the start of every new year in terms of resolutions. But, few are disciplined enough to see it through. And as Clay Christensen says, you will only imbibe it into your culture if you're disciplined enough to avoid the 'just this once' lapses.