The Groundskeeper Willie Natural Enemies meme originates from the Season 10 episode of The Simpsons titled 'Sunday, Cruddy Sunday.' In the scene, Willie explains to Principal Skinner how Scots are natural enemies with almost everyone, including other Scots, famously shouting, 'Damn Scots! They ruined Scotland!' The meme is widely used to highlight internal conflicts within specific communities, fandoms, or professional groups, showcasing how often those with the most in common end up arguing the most.