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What an employer he was. As hard and ruthless as a rose petal.
— Ebenezer Scrooge ‧ The Muppet Christmas Carol

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The comparison overturns the apparent accusation of hardness and ruthlessness: a rose petal suggests softness and gentleness. The speaker makes the description affectionate through that mismatch. Its humour comes from borrowing the language of a severe employer and ending with an image that undermines it.
Context reviewed