If by social psychology you mean: knowing how to navigate social situations gracefully, and form meaningful connections -- then I would say it's the most import

If by social psychology you mean: knowing how to navigate social situations gracefully, and form meaningful connections -- then I would say it's the most important skill even over technical ability. However viewing it as Machiavellian/adversarial makes me feel like you have the wrong perspective on social skills. Fostering a culture of trust and connectedness is the key; deception is part of the game but no more than a tiny percentage of it.