negative nancies

Someone who commonly whines, complains, or looks at the bad side of things.
> 2nd grade teacher: "All right kids, today we're going to learn an important lesson: how to pack your rock into your crack pipe."
> Johnny: "But Mrs. Stoner, my mommy told me drugs are bad."
> Teacher: "Johnny, stop being such a negative nancy. You'll never get anywhere in life with that attitude."
> Johnny: "But, my mommy said..."
> Teacher: "Johnny, please shut the fuck up or I'll send you to time out and brutally murder your family."