THIS IS SO CUTEE ðŸ˜ðŸ˜ðŸ˜ðŸ˜ðŸ˜
Headcanon that although Snape doesn't laugh much, when he does, it's not the laugh anyone expected from someone like him. It's the laugh of someone much younger, the laughter of a child. It's the laughter of a girl.
It's the laughter of Lily Evans, the girl who taught him how to laugh.
So sometimes he'll start laughing at something, and the other teachers will stop for a second, because they remember that laugh, that's how Lily used to laugh. McGonagall remembers how Lily would laugh, Lily was one of her top students after all, and god did she remember that laugh.
One day Harry thought he heard his mother laugh. He knows the way she sounded when she laughed thanks to an old recording where he was laughing with him. And he thought he could hear her.
When he looked, however, he could only find Snape, laughing at something McGonagall had said.