DC2 and I have been watching Blackadder together- it's his first time and probably my ninety-fourth.
We've just got to series 3 (the best one) and come to the phrase "Sensible policies for a happier Britain!" which DC2 has probably heard me, his DF, his DGPs, and his uncle use weekly for his entire life. (I remembered it as being from the scene with Vincent Hanna but actually it's from Sir Talbot Buxomly, earlier in the episode - none of my previous viewings were this century).
At age eighteen he finally knows where the phrase comes from. His 21 year old sibling is away at uni and still unenlightened.
What's the oldest your DC have ever learned the origin of family catchphrases?