The phrase you gou ben comes from everyday Taiwanese Mandarin, where you gou is used to intensify an adjective, so the expression simply means extremely stupid in a colloquial, teasing way. It has become a familiar reaction phrase in Mandarin-speaking online communities, shared in short clips, memes and chat conversations when someone does something obviously foolish. Because the wording is short, expressive and easy to repeat, it works well as a soundboard reaction that needs no explanation, and it continues to circulate as a lighthearted way to call out a funny mistake.