It's all in the pronunciation I believe.

"What are you wearing?". "Eau de diesel, my dear".

As opposed to when your wife asks you what you were working on in the shop and then answers her own question with a wrinkle of her nose, "Oh, the diesel".

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“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now