It's interesting that so many of us tend to be "hard on ourselves." I certainly fall into that category.
I have a friend whom I've helped out a lot in weapons practice leading up to her shodan test. One thing I told her was to stop saying, "I suck at this weapons stuff." I felt that harboring those kinds of negative thoughts about herself could only be stumbling blocks and a crutch on which to lean upon.
Frankly, it still pains me when I hear from her that her weapons sucks. I feel like I spent a fair amount of time helping out and to hear those words come out just makes me think that I did no good. I, of course, know it's not the case, but it's sad to hear it nonetheless...