It's called an "inner critic." Inner critics are terrific at sabotaging our intentional goals.
Psychologist Lane Arye writes about working with an inner critic in his book
Unintentional Music: Releasing Your Deepest Creativity:
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Have a chat with your inner critic. You can do this on paper, or out loud, as you prefer. The first step is to bring it out of hiding. Ask your critic what it does not like about you. This may unleash a furious barrage that may be hard to listen to, but don't be discouraged. You are only priming the pump, getting your critic comfortable by asking it to talk about its favorite subject. When it starts to run out of steam, or when you've had enough, shift the topic. ...
1. Ask your inner critic what it does not like about you.
2. Find out your critic's goals.
3. Ask your critic to help you meet those goals.
4. Don't take "no" for an answer. (Critics are lazy. Oh, yeah, they work overtime bugging you. But try to get them to do some real work, like help you with a creative project! Then they make all kinds of excuses and say it is your job.)
5. Criticize your critic. Tell it that if it were any good at ... clarity, beauty, whatever ... it could tell you more specifically what to do to meet your common goals.
6. Be merciless, just like your critic is -- don't give up until you have gotten the help you need.
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It's simple, but it isn't necessarily easy. The two toughest parts of this are (1) being able to hold a conversation with a particular part of yourself in the first place; and (2) standing up under the shower of vitriol a determined inner critic can spew at you.
Hope this helps.