At sixteen Minerva McGonagall did not like Transfiguration, she excelled at it, but she did not like it. Minerva McGonagall's calling was Quidditch.

At sixteen she was the best seeker Hogwarts had ever seen. If that snitch was out there, Minerva McGonagall would find it, and find it fast too, she broke her own records every match.

At seventeen a devastating Quidditch accident (Broom, bludger, niffler, the words still brought chills to her spine) ended her career and left her with a rather funny looking scar. Very funny looking.

At 79 Minerva McGonagall may have turned to teaching, but that particular broom still hung in her sleeping quarters. And that particular Niffler still served as a brilliant mantle ornament, in the teachers lounge.