In detective land, you have to deal with a lot of intense emotions, so you yourself have to remain mostly unemotional and detached. These are people, like law enforcement and surgeons, in professions that don't have the luxury of being able to be emotional or to break down. In my line of work, it's almost a requirement.
When I did 'The Sound of Music' and 'Mary Poppins' and 'The Americanization of Emily,' all three were in the can and had not yet been released. So I was driving around having a fine time learning about how to make movies and enjoying myself enormously, and then they were released, and it was quite an assault, in a way.