That and some actors are just used to it. Ian McDiarmid is not a better actor than any of the other of the cast and yet to me he comes off just thatmuch more skilled- but then again its old hat to him. He's played the role, he knows GL's style and he seems comfortable just saying and doing whatever.
And as far as the tennis ball, Tom Hanks did pretty well with a volleyball for a co-star.
