On Sunday's episode, Peggy was faced with choosing between career and personal life. Perhaps she didn't even realize that unlike many women of her era—including those like Trudy Campbell who pity her—she actually had a choice to make.
As Peggy was about to celebrate her 26th birthday by having dinner with her boyfriend, Don—who's been filling his own empty life by pouring himself into his work, and pouring himself another drink—wanted to avoid the inevitable bad phone call regarding the original Mrs. Draper's death, and assumed that Peggy didn't have anything better to do than work on the Samsonite campaign either. Ironically, he was right. When faced with having dinner with a family and boyfriend who clearly don't understand her or staying putting in overtime with her drunk of a ball-busting boss, she made her decision pretty quickly.
While at first she seemed annoyed at Don, it became clear to her, as the night progressed, what really mattered to her, saying, "I know what I'm supposed to want but it just never feels right or as important as anything in that office."
Well-intentioned, yet backhanded comments like Trudy Campbell's probably only added to her initial confusion. ("You know, 26 is still very young." Read: "You're not an old maid yet. There's still hope!")
The same is true for the rumors floating around about how Peggy slept with Don to get her job. The gossip—that she got her job, not because she deserved but because she put out for it—doesn't bother her as much as the fact that the other girls in the office find it laughable that a handsome guy like Don would stoop to having sex with someone like Peggy. In the same way that Peggy acknowledged that she knows what she's "supposed to want," the same could be said in this instance. She's been taught, as all women have, that she's supposed to be wanted, desired. It doesn't upset her that Don didn't chase her around her desk. But she finds it insulting to her looks. This—unlike some of the progress that women have made (like the ability to choose) since 1965—is a problem that seems to persist to this day.
The fact that implementing change is a long process was reflected in last night's episode as well. Like the general public's refusal to refer to Cassius Clay as Muhammad Ali, as he'd already changed his name by this point. Also, it's been a few months since the Selma marches, and President Johnson had already sent the bill which became the Voting Rights Act of 1965 to Congress. (It was passed by the Senate the day after the Clay/Lewiston fight.) But still, there are casual racist remarks thrown around the office, like Jew jokes, Miss Blankenship's "negro" remark, and Peggy's admission that her mother's attraction to Nat King Cole caused her father to dispose of his albums.
But as far as Peggy's insecurity about her looks go, weirdly, Don, a notorious womanizer, attempts to cheer her up by explaining that he has "rules" about sleeping with coworkers. While he and Peggy (and the audience) know this isn't true, what becomes apparent is that Don doesn't view Peggy as a "skirt" but as a person, and one of value.
Over the course of the night, Peggy and Don open up to each other for the first time since he visited her in the hospital after she had Pete's baby. He comforted her over her breakup, and she over the death of his friend. He sobs that he lost the only person who really every knew him. Peggy tells him he hasn't. And he must realize this is true, having spent a night getting personal with a woman without having sex with her.