The one thing that really holds INTPs back is their restless and pervasive fear of failure. INTP personalities are so prone to reassessing their own thoughts and theories, worrying that they've missed some critical piece of the puzzle, that they can stagnate, lost in an intangible world where their thoughts are never truly applied. Overcoming this self-doubt stands as the greatest challenge INTPs are likely to face, but the intellectual gifts – big and small – bestowed on the world when they do makes it worth the fight