The 'First rule of the Fight Club' meme originates from the 1999 cult classic film Fight Club, where character Tyler Durden establishes the underground group's strict code of secrecy. The humor in the meme typically stems from applying the 'do not talk about it' logic to various situations, or conversely, highlighting people who can't stop talking about specific topics like diets or hobbies. It became a cultural phenomenon due to its stark delivery and the inherent irony of a secret club that everyone in pop culture knows about. Today, it is a staple for mocking groups that lack self-awareness or for emphasizing a strict, unspoken social rule.