Mindset

Carol Dweck wrote a groundbreaking book that studied important differences between the "fixed" and "growth" mindsets. She posits that individuals are likely to develop a mindset that their intellectual traits are either fixed or malleable. The growth mindset is demonstrated produce more success through hard work, wheras fixed mindset indivuals are more likely to fear failure and simply try to "look smart".
This book completely changed the way I think about my own abilities and I think that the core concepts of the theory should be taught in schools, even if more for the educators sake. For instance telling a student "Good job, you're very smart" vs "Good job, you worked hard" are likely to be influential.