That's how it's done... if you can be cheerful and upbeat. Sadness, however, is neither of those things.

But she forces herself to try. "Oh... um... h-hi... I'm... I'm Sadness..." She feels the pressure mounting on more and more as everyone looks from Joy to Sadness. "It's... it's nice... to meet... you all..."

Well, she made it through without crying or sniffling. That's an achievement, right? Right?? At the very least, the giggling seems to stop after that. A portion of the class seems to feel sorry for her now, if the looks they're giving her seem to indicate.