The way you speak about yourself teaches your mind what treatment feels normal.

The words you use about yourself are not just description. Your mind takes them as instruction about what is normal, and the standard it forms from them quietly sets what you will accept from others. Someone who calls themselves useless every time they fumble is teaching themselves that contempt is the natural response to their mistakes, and will find contempt from other people unremarkable when it arrives.

Catch one phrase you use about yourself automatically and hear it as though someone else said it to you. If it would be unacceptable from them, it does not become acceptable in your own voice. Replacing it with something plainer and more accurate is a small change that reaches further than it looks.