I've been thinking lately on what makes a good red herring. So far, my thought leans toward bad red herrings wasting the reader's time while revealing nothing and good red herrings contributing to the story. Though plot contributions can feel suspiciously convenient—that clue was wrong, but they stumbled on the villains' lair anyway!—the dead ends can be useful explorations of characterization. But I'm sure there's more. What makes a good red herring, and what might make one bad beyond simply wasting time?
Examples always help me, so if any red herrings done well or poorly come to mind, I'd love to hear them, along with any positive or negative aspects about how they were employed.
by PASchaefer