Mad Men - Joan, Betty, Peggy
Credit: Courtesy AMC (3)

Warning: Major spoilers ahead for those who haven't seen the final episode of Mad Men. We've all done our fair share of over-analyzing the iconic series, and whether or not you were pleased with its ending, one thing is certain—we had quite a few plot questions we were dying to ask creator Matt Weiner to address. Last night at the New York Public Library, we got some answers as Weiner sat down with writer A.M. Homes for a talk in which they discussed the end of the series, the themes of the final episode—and of course, the significance of the Coca Cola ad.

"I did hear rumblings of people talking about the ad being corny. I'm not saying that advertising isn't corny, but the people who find the ad corny are probably experiencing a lot of life that way, and they're missing out on something," Weiner explains, noting that when he showed Kiernan Shipka the ad, she mused over how beautiful the song was. "The idea that some enlightened state might have created something that is very pure—to me, it's the best ad ever made, and it comes from a very good place."

Among the topics covered in the discussion, like the coincidence that the pilot was shot on the exact floor of McCann Erickson's creative team circa 1970, Weiner also had a few revelations about the series' leading ladies, all of whom went under some of the most transformative character arcs we've ever seen. Read on to find out what he had to say about Joan, Betty, and Peggy's roles in the series.

Matthew Weiner - Embed
Credit: Jori Klein/The New York Public Library

Joan's Storyline Was the Most Surprising Plot-Twist for Weiner
"First of all, if you would have asked me in the pilot, I wouldn't have known Joan was going to be a main character until I met Christina Hendricks," Weiner says. "I definitely didn't think that Joan would be this single mom feminist, looking for child care on her own, and I love the fact that it's not philosophical for her. This woman made a practical decision to not take any sh-t anymore." He notes that, during the episode in season 4 when Joan makes an appointment at an abortion clinic, Weiner thought she would actually go through with it until speaking with his writer Maria Jacquemetton. Their conversation made him realize the importance of including a single mother storyline. "There is a lesson to be told there—lots of people are raised by single moms, and actually, some of the most successful people have been raised by single moms," he says. "It's a tough road to go, but I think more than half the presidents have been raised by single moms. It was a shock to me, and I just loved it."

He Knew Betty's Fate Very Early Into the Series
Though the news that Betty was dying of lung cancer was shocking for the rest of us, Weiner had determined as early as the fourth season that January Jones's character would eventually meet her end. "Her mother had just died in the pilot, and I felt that this woman wasn't going to live long," he says, noting the scene between Henry and Betty following her diagnosis as she plans to return to school. "We loved the idea of her realizing her purpose in life right when she ran out of time. I think there's a lesson to be learned about the randomness of things, and also, she had a predisposition to some fairly serious cancer-causing behaviors, right up to the end." At the time he had determined Betty's fate as he wrapped season four, Weiner also knew about ending with the Coca Cola ad, though Peggy and Stan's plotline took a little convincing...

Peggy and Stan's Over-the-Phone Declarations
Fact: Many of us called the chemistry between Peggy and Stan very early on, but Weiner needed further proof. Once he saw it, their confession of their feelings only seemed appropriate to share over the phone. "It's funny, because it's bad for drama. I was told, 'It's a big scene! Get them in the same room,'" says Weiner. "I feel like a lot of the most important things that have ever happened to me in life have happened over the phone. It's a dramatic situation almost every time you answer the phone." The entire scene also echoed how, oftentimes, people can be more intimate over the phone than they are in real life.