There are many parts from the Harry Potter books that didn’t get included in the movies at all that I wish they had included.
And the part where Harry casts the Cruciatus Curse on Amycus Carrow because he spat in McGonagall’s face is one of them.
That whole part was just brilliant because after McGonagall realized who did it, she called him foolish for doing it and all he responds with is, “Bellatrix was right, you really have to mean it.”
He had so much respect and admiration for McGonagall that he couldn’t stand seeing someone else disrespect her and he felt so enraged by it that he was able to cast the Cruciatus Curse.
Just a random thought.