Remember her brief moment with Trelawney? After Umbridge sacks her, McGonagall guides her away, saying supportive things. It's not a grand quote, but the action—physically supporting a colleague she often found ridiculous—shows incredible solidarity and kindness. She sets aside personal annoyance to defend a fellow teacher's right to exist and work at Hogwarts. That professional loyalty has a deep core of human decency.
"I will not have you, in one night, undoing all the good work I have done teaching you dueling." Said to Amycus Carrow. It’s a defiance that’s deeply professional and inspiring. Even facing evil, her primary identity is as an educator protecting the integrity of her teaching. That’s dedication to craft in the face of darkness.
Her humor is so dry it could parch the Sahara. Take the moment she tells Peeves the chandelier unscrews the other way – it's not a joke, it's a weaponized instruction delivered with perfect deadpan timing.
Her leadership includes a deep sense of theater. Leading the teachers with lit wands to protect Harry's body is a public, symbolic act of defiance. She understands the power of a visual statement to rally and mourn simultaneously.