When I first watched The Conversation, I smiled when Harry Caul makes a point about not using God’s name in vain.  I used to do the same thing and it freaked people out in the same way.  I wanted to force order to those around me just as he does in the film.  The entire film is filled with truthful moments  - like the way in which he builds the nerve to brag relentlessly in the face of his competitor and his later reaction to being upstaged.  He’s intent on order and his own privacy, but it’s only out of fear of losing them.  It’s this paranoia that keeps him from engaging in a normal life and when it comes crashing down on him it’s sad, beautiful, and the makings of a masterpiece.