when I kiss a guy who has a mustache I'll close my eyes and pretend he's either Mario or Luigi, depending on his height

Poor Luigi when his parents were all, "This is Mario, we also call him 'Super Mario'. And this Luigi, we also call him 'Player 2'.

Mario and Luigi fight to the death, in "The Plunger Games".

Princess Peach: Something's different. You seem taller. Luigi wearing Mario's red overalls: No, nothing is different. It'sa me, Mario.