The informant is 50 years old and from Riverside, California. She describes a saying popular in her fishing-obsessed family: “as smart as bait”.
As stated, the informant grew up with a father who took her fishing frequently. He was the main perpetrator of this saying, jokingly using it during fishing trips. However, it was also used in regular life, it became adopted by all of her siblings and her mother, and they used it whenever they wanted to call something stupid. According to the informant, “Fishing bait is the least desirable thing to be in the world. Not only does it smell bad, get pierced by a hook, and eaten by a fish, it looks like absolute mush. There is nothing impressive or intellectual about bait, so equating another person’s intellect to that of bait is a major insult. That said, the tone of voice that this phrase is said in is usually very lighthearted and joking, so it doesn’t come across like a major insult, but instead like a light tease.”
I’ve heard a lot of folk sayings that use the form of a simile to insult. “As smart as bait” reminds me of other sayings like “smart like a tractor”, “dumb as a doornail”, etc. What’s interesting to me is that both “as smart as bait” and “dumb as a doornail” mean the same thing, despite one using the word smart and one using the word dumb. Irony goes a long way here, but it’s interesting that an insult is assumed of both.