Introverted Thinking (Ti) is the function of living logic. It is a code of reason. It seeks worthy principles, and takes personal pride in having discovered and adopted to principles.
Ti is cutting, having no compunction against pointing out a flaw and poking it, like a swordsman jousting to attack the vulnerable spot.
Ti is efficient. It has no use for carrying around an inefficient method when a better one is found. There is no sentiment for old methodologies.
Ti is logic personified. Its bearers are an expression of this personalized logic, and challenges to the logic can be taken personally.