The challenge is that ALL people think they are thinking people. That is good because it would be one of the worlds saddest moments if people wandered around thinking "oh my God - I cant think - Im just a waste!" What good would that do, really?
False dichotomy. Recognizing you lack a skill does not mean you therefore think you are a waste. This is a perfect example of an opportunity to correctly blend critical thinking with compassion. If, for instance, someone lacked critical thinking skills by say, using a false dichotomy and then thought they were a waste, a person with good critical thinking skills would realize that isn't true and offer to help with that and point out that he or she isn't a waste but just needs to learn a skill.