1) Being sad/mad/scared/worried/bored/tired. Silence does not necessarily equate one of those six simple states of being that many less emotionally discriminating people are determined to categorize the world as. How many effing times have I heard: "Omigod, are you alright!? Are you... sad/mad/scared/worried/bored/tired?" No, but if I was, I probably wouldn't discuss it with you. And you're going to be when I hit you in the face for asking that question umpteen times.
Where is point 2)? :confused:
"A man who only drinks water has a secret to hide from his fellow-men" -Baudelaire