Blaming yourself decreases willpower. Forgiveness raises it.
“Study after study shows that self-criticism is consistently associated with less motivation and worse self-control. It is also one of the single biggest predictors of depression, which drains both “I will” power and “I want” power. In contrast, self-compassion— being supportive and kind to yourself, especially in the face of stress and failure— is associated with more motivation and better self-control.”