Don't I know it!
I'll never forget the lady who got mad at me for messing up her "plumbing". I'd repaired her toilet (I'm a plumber, originally) and the day after I left, her kitchen sink started leaking. She was furious, when I refused to repair it for free!
In her mind, I'd worked on the "plumbing", and after I left, something went wrong with the "plumbing". Ergo, I did it. There was no arguing with that.
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