It's happened to all of us. We think, sometimes for years, that the lyrics of a song are one thing, but it turns out to be something totally different.
For me: I used to think Billy Idol was saying, "How's about a date" instead of "Eyes without a face".
How about you?
DISCLAIMER: Is there at least one related thread on this topic? Probably. Am I going to bother to try and search for it? Absolutely not. So there!