Picture a pot already simmering on someone's stove. Nobody cooked it for you, nobody asked what you wanted, and the lid is still on. You sit down, the lid comes off, and you eat what is in there. One way to hold pot luck is that image: not knowing in advance, and taking what comes.
可以想成爐子上已經在煮的一口鍋。沒有人為你特別開火，也沒有人問你想吃什麼。蓋子還蓋著，你坐下來，掀開來才知道裡面是什麼。pot luck 的幾種用法，一種想法是都從這個畫面長出來——重點不在東西好不好，而在「事先不知道，然後接受端上來的」。