A thought: The saying "Even a broken clock is right twice a day" only applies if the clock is stopped. If the clock is running fast or slow it'll be right much less often, and if it's just plain set wrong it'll never be right.
And taking the analogy to people as it usually is, a stopped clock would be an uninformed person talking as though they know what they're talking about, a fast or slow clock would be a misinformed person, and a mis-set clock would be someone acting with malice.