Breaking a commitment the first time is harder than the second time. It's obviously a generalization and may not be true for all situations.
I've committed to write and publish every week day. Today is one of those days that it'd be too easy to not publish. So many good excuses that I could rationalize to allow breaking this commitment. But I know that if I do that today what stops me from doing it again tomorrow.
I'm not ready to break this commitment. I'm not done writing daily. I'll stop when I make that decision.
Today I write before I go to bed. Today I need to push through and it feels like I won something.