A mother you're acquainted with insists upon setting up a play date between her little devil (partial to toys that can injure and South Park) and your little angel (kind to creatures great and small).

YOU SAY: "This isn't a good time for our kids to get together. Little Johnny hasn't been in the mood for play dates recently. He's been going through a low-key phase."

WHY: "How can you tell a parent her child is a nightmare?" says Anita Sethi, director of research at the Child and Family Policy Center at New York University. "If the parent finds out that your child is indeed having play dates, just not with her child, she'll get the message indirectly."