I just read "pet peeve" in the "French Red Apostrophe's" thread, which reminded me...
I was probably 8 or 9 the first time I saw this expression, and I had no idea what a "peeve" was.
Since I couldn't figure it out from the context, I wondered what kind of animal a peeve was: mammal, bird, fish, etc. Those were the kinds of things I knew were pets, and since the writer mentioned losing his pet peeve, I thought it might have died or escaped. The name sounded a bit like it might be a bird like a parakeet, or a small mammal like a pika, both of which also happened to start with "p".
So I went to the World Book Encyclopedia (yeah, it's what we used in Ye Olden Tymes), took out the "P" volume, and looked for "peeve". Nothing. Well, that's weird.
So next I went to the Webster's Unabridged Dictionary and looked up "peeve". Huh. Well that's nothing at all like I expected. More a metaphorical pet than an actual one.
Since then, I've thought that if I ever got a parakeet I'd have to name it "peeve". I'm not really a pet person, so that hasn't happened. If anyone else wants to use it, I won't complain. It'll be your pet, "Peeve", not my pet peeve.