at the same time, tried to limit you to treating him at the personal level. Such disparity enhanced his dominance over you.
His insomnia was just a bait.
You cared. That should be a good thing. Imagine a place where nobody cares.
But everything comes with a price. Care also brings with it expectation, which burdens on people's unconscious because you have off-loaded it from your own shoulders.
He shoulders his own by not giving a damn. When he uttered "stupid design", it's like a dog barked for its master to hear, and the manager felt a great relief but still shouted "Stop it! Rover."
So, what you need to ask is: why do I care? Is that they need my care, or I need to care? One has to be self-aware enough to answer.