You are not a bad person because you did not resist the temptation to eat that bar of chocolate or procrastinated on that project at work until it was too late to do a decent job. Stop beating yourself up and feeling bad about being human.
Instead of making excuses to your imaginary drill sergeant, try to see that for an action you take there are reasons. If you did not have enough willpower to resist the lure of chocolate, you are not a bad person, you are a person whose willpower was depleted. If your willpower was depleted, you can plan ahead to make sure that your willpower will not be as depleted in following instances. Self- castigation will accomplish no more than making you feel bad – which is not at all beneficial to your willpower or self-confidence.
When you see that your actions have reasons from your environment or mindset instead of being an irreparable character flaws, they become only a minor obstacles to be avoided or planned for.
To happiness, and beyond!