So you messed up.
Maybe you were on a diet, but you just ate a bag of Doritos. Or you're trying to get into a workout routine, but you skipped the gym to watch House of Cards. Or maybe you caught yourself wasting time when you promised yourself you'd finish that presentation by noon.
It's tempting to beat yourself up about it. "I'm such an idiot! Why can't I do this?"
But that's not useful to anyone. You know what's useful?
Getting back to work.