12. "Six Month Leave" (Season 2, Episode 9)
Freddy Rumsen gets fired from Sterling Cooper for being a drunken mess, which is like Steven Adler getting kicked out of Guns N' Roses for doing too many drugs. Don and Roger send him off with one last bender, hitting an after-hours speakeasy casino. ("Is it Milwaukee?" "Yes, it is." "Son of a bitch.") But the night only reveals how desperately screwed up all three men are: Mike Moneybags, Dick Dollars and Tilden Katz.
Best line: "There's some incredible woman, and someone's going to end up with her, but it can't be you."—Roger Sterling