You're just making an assertion that my claim is incorrect. Practical experience shows - consistent effort does indeed deliver results, and leads to improvement in capability (by and large - as pointed in my original answer). For example, the whole education effort of 14-15 years is full of painful experiences, getting wrong answers in math, flunking in laboratories, etc. There is stress involved during the examination. If I simply avoid the exams citing stress, how'd I ever become capable?

Therefore, I don't see how you could be correct on this.