29. Victoria's Truth Bomb (Season 7, "Ducky Tie")
Sure, the audience had been scratching their heads for a few seasons, mystified and a little bored by Robin's ping pong between Ted and Barney. But the characters rarely addressed how weird the situation was until a returning Victoria (Ashley Williams), arguably the most significant non-Robin relationship of Ted's life, puts it bluntly: "There is a reason it didn't work out between you and me. It's Robin. She's so much bigger in your world than you realize." It wasn't news to us, but it crystalized the theory that this show is not so much the story of how Ted met the Mother, but how Ted got over Robin. Honorable mention for Barney's long con to see Lily's boobs.