I was in high school when this aired, and was never a TV person. But, I watched Friends every Thursday. When I went to college, I forgot about this show for the most part, but I never forgot this episode. Recently, I gave in and binged Friends for the first time, having not watched it since I was young. And I could not wait for this episode. What I remembered most was the play on words ("They don't know that we know that they know"). It was pure joy at the time, comedy genius. Such a happy time in my memory enjoying this show. When I finally got to watching this episode, it was everything I remembered and more. It is really one of those rare gems that captured a moment in time.
