Emma Thompson in"Howard's End". There is a scene where she learns her husband has had a fling with a lower class totty, but keeps her composure until the last car is waved away, then she crumples.....it is magnificent!
Jack Nicholson was the greatest actor Hollywood ever produced. When I saw him in "Five Easy Pieces" his performance just blew me away. I think he's still capable of wonderful performances (About Schmidt) but too often he's sending himself up.