Working for the past 12 years to help people affect lifestyle changes, I'm still regularly amazed by how hard on themselves people are.
We all fall down. Considering whether or not your personal internal castigation is fair or not is important to the long-term likelihood of your success as if you regularly, unfairly, kick yourself when you're down, you're less likely to ever bother getting back up.
If you find the question confusing, or its implementation challenging, the next time you get down on yourself for some sort of lack of follow through imagine the counsel you would provide to your best friend or closest loved one if they found themselves in your exact situation.
My guess is that you'd be terrific at actively encouraging your loved one to look for the positive, and in so doing, increase your loved one's likelihood of getting back up.
You deserve to treat yourself with just as much love and respect as you treat those to who you are closest.
Are you treating yourself fairly?