It is rude to call people names.
Jane and Jeff are having an argument over something they disagree on.
Jeff wants to convey his frustration with Jane's reasoning.
Jeff points out the flaws in Jane's logic and asks her to reconsider her position.
Jeff calls Jane a complete moron for disagreeing with what Jeff is claiming.
Jane give's Jeff's line of thinking new consideration before forming her final judgment.
Jane is hurt by Jeff's personal attack and refuses to listen to his explanations.