Dinner Party That's What She Said
The 'that's what she said' from the dinner party episode is different than all the rest from the show, did you guys notice? Usually, Michael says it to take something out of context and make it sexual. But in this episode, Jan said 'You're hardly my first' which is already something related to sex. Michael replied furiously 'That's what she said!' but it doesn't make sense because it was already something sexual. I believe Michael was so angry at that moment that he didn't care and said it anyway.
I also want to say that Dinner Party is the best episode in comedy TV shows ever.