The way it was explained to me when I was learning about JW beliefs, one should use his name as much as possible because it pleases him and is a way of being closer to him - being on familiar terms.
However, when I was listening to the last part of hobo ken's recording, it struck me how incredibly disingenuous this is. The way it winds up being realized, a JW strives to be heard by other people using the name Jehovah, so as to make a big public display of their intimacy with God. What a crock.