It was amazing at the end of Eternal Sunshine of the Spotless Mind when the water was rushing into the house around the feet of Joel and Clementine. I do not mean the effects (although they were wonderful), I mean the honesty; for example, when Clementine asks Joel "Was it something I said?" and Joel responds "Yeah."
The tone of his voice was so completely honest. It has to be some of the best acting I have ever seen. I was totally convinced. Genius -- and I dont use that word often.