What is a death scene you just can't watch for whatever reason?

I am not one who is easily disturbed by movies, but I recently watched David Fincher's "Zodiac" and the park scene with the woman screaming as she gets stabbed is just so unnerving to me. The tension is built so well that when the murder begins you are caught in shock thinking it might be alright after the murderer has put away the gun. Really great movie.