dumbest excuse someone gave you for not buying part/ car from you?

My brother once traded his 77 Warlock 318 4x4 and the best pulling car trailer I've ever used for a Harley.

The truck had original paint (although thinning) and wood, ran like a top, and the a/c and cruise control worked.
He told the "tradee" up front that he didn't know if the motor was the original, but had no reason to believe otherwise.

Two weeks later, the tradee calls and demands to be "compensated" because he can't read the numbers on the block, and that the "value may be hurt if the numbers don't match".

Really?

If it was a 440 car, maybe, and if it was that important, I'd have damn sure looked at the block BEFORE handing over the title.