Busy people rarely ever feel sad. Why? Because sadness requires a certain depth of epiphany, a subtle but constant blow in the gut. You can never find sadness lurking in the corners of a busy office or in a library full of curious young minds.
Sadness, I think, is when the world has momentarily left its orbit to embark on a dim lit path. It is there when the day is over and the lights are out and you are left sitting in the dark feeling every bit of human. It is when you'd rather stay in for the rest of the night- and day, as well -because frankly, you have forgotten the difference.