Am blogging from my iPad and still getting used to typing with a single finger. So forgive the compactness of this answer and post. The answer is:exhalation corresponds to dispassion. And an ability to be objective. Since all of us are attached to something or react intensely to something .. Be it good or bad we find exhalation most difficult:) so sharmishta it's not greed but u came close in yr guesswork. It is a sort of attachment.
Today's query: What are the qualities of the standing poses? Interestingly there two qualities to these poses. Both opposite to each other. Think a bit as to what standing poses do to emotionally and how u feel at end of a standing balance?