Fan theories about Friends include the one where Ross loses custody of his son and the one where Rachel is a former lover of Ben Wyatt from Parks and Recreation. One of the most interesting and perhaps most accurate fan theories, however, recasts Friends characters as the seven deadly sins. The seven deadly sins are the biggest no-nos when it comes to virtuosity: lust, gluttony, greed, sloth, wrath, envy, and pride.
You might imagine Joey as lust, or Phoebe as pride, but the fans who developed this theory took a more in-depth look at Friends. It almost seems the writers meant to cast the seven deadly sins as Friends characters.