Frank Sinatra, 'My Way' (Season 7, Episode 6)
Women may come and go in Don's life, but there will always be one constant: Peggy Olson, his protege-turned-peer. And much like the landmark Season Four episode "The Suitcase," this episode focused on their relationship, as they find their way back to each other and work their magic as a team once more (for Burger Chef, of all things). They open up to each other — with Peggy admitting her anxiety about turning 30 — and realize that they are, in a way, family. Sinatra's "My Way" comes on the radio, and the two share a dance; it’s a sweet moment for Don and Peggy, who've always had a bond that skirts the line between mentor-mentee and father-daughter. In this moment, it certainly felt like the latter.