4. "The Good News" (Season 4, Episode 3)
A few deeply damaged people spend the final days of 1964 together — Don heads out to California to visit Anna, then returns East for a weird New Year's adventure with Lane. They heckle a Japanese monster movie before meeting a couple of lady friends in the Village. So many painfully intimate moments: Don painting the living room with Anna, Joan throwing roses at Lane, Don slow-dancing to "Old Cape Cod" with Anna's proto-hippie Berkeley niece. This episode sums up what the Mad Men story is all about: Lonely people trying to take care of each other, and failing.
A casually prophetic aside from Joan: "I'll have Megan clean this up." Oh, there will be plenty of messes left behind for Megan to clean up.
Best line: "She does not go to Barnard."—Don Draper