Executive Meddling: Resulted in a six-month delay to Season Five. Contentious negotiations between AMC and Matthew Weiner eventually led to a deal which included shortening episodes by two minutes, increased product placement, and possibly trimming the cast.
Fake American: Deliberately averted by Matthew Weiner, who refused to cast English actors as Americans (thus making him the American answer to J.K. Rowling in that sense). Hence Jared Harris being a seemingly rare English actor on an American series who gets to keep his regular accent.
Finn DeTrolio is a Lenny Bruce-esque stand-up comic in "Christmas Comes But Once A Year", Kelli Moltisanti is Dr. Faye and "Little" Carmine Lupertazzi Jr. is the concierge at Don and Megan's condominium. No surprise, since Matthew Weiner was basically Number Two after David Chase on The Sopranos in the late seasons.
Lois's actress, Crista Flanagan, is possibly the only person who can say they've been in both Mad Men and Seltzer and Friedberg movies.
Wait, is Eden McCain really just Don's neighbor, or is she spying on him for Primatech Paper?
Pete Campbell can often be one of the more detestable characters in the show. Vincent Kartheiser, on the other hand, is generally a good-humored guy, if his participation in the Nerdist bowling episode is anything to go by.
Rich Sommer comes across as quite humble in contrast to Harry Crane (at least the Harry of the last few seasons).
McLeaned: Lane was killed off in part because Jared Harris had too many other upcoming acting commitments (especially with playing Professor Moriarty in the new Sherlock Holmes films). There were no hard feelings, though; Harris recognized he was simply too busy.
John Slattery's real life wife Talia Balsam plays Roger's wife Mona. Rather amusingly, their characters get divorced so that he can marry a twentysomething.
Creepy little Glen Bishop is played by Matt Weiner's son.
Romance on the Set: Alexis Bledel (Beth Dawes) and Vincent Kartheiser (Pete Campbell) played two people in an affair in Season 5 (early 2012), officially started dating in October 2012, and got engaged in March 2013.
Star-Making Role: For practically everyone on the show since the majority of the cast were unknowns or only known on niche shows before the series launched. The notable exception is Robert Morse, who has been a name for decades.
John Slattery originally auditioned for the role of Don Draper, but the production team felt he was too old.
Jon Hamm originally auditioned for Jack Donaghy on 30 Rock. One wonders who they'd have cast as Don without Hamm.
According to one interview, BECK turned down repeated offers to write the show's theme song, since at the time he thought it would never catch on: "Itís about ad executives in the í60s? Theyíre going to make a show about that? Really? Um, I donít think so".