8. Maggie Smith (Professor McGonagall)
The Harry Potter franchise introduced Maggie Smith to a whole new generation of viewers, and though her performance as Hogwarts' stern Professor Minerva McGonagall has been widely praised by fans and critics alike, Smith isn't so fond of the part.
She said of both her work on Harry Potter and Downton Abbey:
"I am deeply grateful for the work in Potter and indeed Downton but it wasn't what you'd call satisfying. I didn't really feel I was acting in those things."
Smith added that she only accepted these roles because offers for stage acting - her preferred performance medium - were drying up, and later talked about how "exhausting" working on Potter was:
"I used to find the most exhausting thing was wearing those hats. They're the heaviest things in the world. I had a hat, it was like the Albert Hall, it was huge and so heavy. I was in the snow for about a week with that daft hat on my head for Harry Potter and sitting in that trailer day after day and not being used - that doesn't make you feel too jolly."