Maybe Alan Greenspan didn't take it far enough. A salesman looking to close a deal should do his of her best to induce a warm wave of good feelings. Remember, a happy customer is a rather less critical customer. Still, there is argument that sadness is always the right mood for the task at hand. "Positive mood seems to promote creativity, flexibility, cooperation and reliance on mental shortcuts. But when attention is to detail and gimlet-eyed appraisals are critical, the grumps have it."
Bliss, you could say, is ignorance. These gems of wisdom were taken from Eric Felten, WSJ