Instead of merely setting the mood like the boogie-down radio hits inserted into every other scene of CBS’s ’70s period drama “Swingtown,” the props and hairstyles and even real TV footage used on “Mad Men” serve to intensify and enrich its picture. After what’s supposed to be a romantic overnight stay at the Savoy, Don and Betty end up smoking in bed and watching Jacqueline Kennedy give a tour of the White House on TV. “It’s so important, the setting in which the presidency is presented to the world,” the first lady breathes in that oddly artificial, film-starlet-whispery voice of hers, and the surreal cultural moment shimmers around the room, revealing new shades of pain and resolve in this disconnected, fractured marriage.

Later, Betty’s friend Francine tells Betty of the broadcast, “She [Jackie] seemed nervous. Even when she saw Jack at the end, it was like they were playing house.” Betty, who often appears to be playing house herself, responds with a lie: “Well, I’m sorry we missed it. No time for television!”

While “Mad Men” may look good enough to write off as style over substance, its style forms an essential part of its substance: When Betty dons the perfect ’60s riding gear with flawlessly applied lipstick or Peggy primly strides through the pristine offices of Sterling Cooper, shoulders squared, bullet bra protruding confidently, to inform Draper’s secretary that her snide attitude is inappropriate, the perfection and gloss of what we’re seeing belie the improbably enormous expectations that society placed on human beings during these times. Even young people were expected to be smooth and flawless and professional under every circumstance. There’s something in those pretty trays of food on the table at meetings, something in the gleam and shine of every office surface, that says, “We stand firmly against the messiness of mundane life. The truth is not welcome here.”

Of course, the less welcome it is, the more the truth manages to wrangle its way in the door and crash the party. When head secretary Joan Holloway (Christina Hendricks) reminds her former lover and current boss, Roger Sterling (John Slattery), that she’s practically engaged, saying “I already know what day he’s going to ask me,” she’s clearly revealing that she’s more than a little nervous that the day will never come. Later, when she berates another former lover, Paul Kinsey (Michael Gladis), she pretends it’s all in sport, but it casts another shadow of doubt on her supposed happiness.

There’s something artful in the ways that these characters balk and back away from each other under duress, and then find roundabout ways to tell each other the truth. At the end of last season, Betty chose not to confront Don about his cheating, instead “confessing” to her psychiatrist that his infidelity made her unhappy, knowing that the information would get passed along to her husband. She’d watched her friend Francine break down in tears, then threaten to poison her cheating husband, Carlton, and even her children — all of it so shocking and undignified! Betty chose to keep her mouth shut, and the truth of her desperation came out only when she ran into Glenn, the little boy who had a crush on her, waiting for his mom in the parking lot of the library. “Glenn, I can’t talk to anyone, it’s so sad,” she confessed, and then begged, “Please tell me I’ll be OK!”

Instead of staying suspended in this vulnerable state, Betty seems to have swept any ugliness under the rug and moved on, concerning herself with her own interests and curiosities. When she and Don run into a former roommate of Betty’s who’s apparently become a prostitute, Betty can’t stop talking about her, and then finds herself flirting with a dangerous situation as if to test her access to her own dark side. We’ve never seen Betty act out or assert herself quite so boldly before. When Francine and Carlton come over to play cards and Francine mentions a book she’s read about child rearing, Betty responds pertly, “I don’t need a book to know what little boys do.” Don flashes her a look of admiration and shock, wondering where this confident woman came from. Then, after the couple leaves, Don mentions that Carlton might be unhappy, inciting an indirect discussion of their own marriage.

Betty: He should be happy and grateful. He should be showering Francine with love after what he put her through!

Don: Look, Betts, I’m not going to fight. Now say whatever you think I should say, but I’m not going to fight with you.

But Betty is no longer interested in Don’s reassurances — she steps outside to smoke a cigarette alone.

The stylish, coy tone of “Mad Men” pervades every layer of the show. The time period almost acts as an antagonist in this picture: We see how the cultural norms and expectations injure each character’s spirit. There’s a heartlessness to these boom times; the future is fast approaching, and those who don’t climb on board the rocket armed with easy cheers and enthusiasm will be left in its smoggy wake. Times of rapid change and economic expansion aren’t made for the pensive or the second-guessing. Loyalty is never rewarded — anyone and anything might need to be abandoned at a moment’s notice for the sake of progress. Duck Phillips (Mark Moses), who’s joined Sterling Cooper on the account side, reflects this attitude the most directly, pressuring Don to make changes that feel arbitrary, fickle and unsound. After protesting the unfair treatment of a loyal client, Don asks Roger, “What kind of a company are we going to be?” Roger responds, with a smirk, “The kind where everyone has a summer house?”

While every scene contains some nugget of this ruthless mind-set, sometimes it’s the exchanges between minor characters on “Mad Men” that echo in the most devastating pitch. In one of my favorite scenes of the second season, Joan berates Don’s new secretary, Lois, in the hallway of the offices:

Joan: Lois, may I speak with you? Theresa said there was an incident yesterday? You were crying in the break room, which I have specifically forbidden.

Lois: I’m sorry, but Peggy …

Joan: Miss Olson?

Lois: She yelled at me.

Joan: Why would she do that?

Lois: [Nervous pause] I’m good at my job!

Joan: Next time you come to complain …

Lois: [Almost through tears] I wasn’t complaining! You wanted to talk to me.

Joan: This is why I don’t allow crying in the break room. It erodes morale. There’s a place to do that, like your apartment. And I would correct your attitude towards Miss Olson. It’s unbecoming.

Here’s the true brutality that lies at the foundation of American notions of professionalism: Emotions are unseemly and should be hidden at all costs. Even if your boss or co-workers would never say such things if they encountered you in tears, there would be an undercurrent of disapproval as they comforted you. “Do you need to talk about it?” in a professional setting really means, “Go blow your nose and get back to work.”

Along with the unforgiving nature of the workplace, “Mad Men” almost luxuriates in the sexism of the times. The degrading offhand remarks about women are too plentiful to count, but instead of making the whole show depressing or disturbing, there’s some strange charge that comes from seeing these attitudes bandied about in the open. When a colleague asks Peggy to fetch something or tells her, without thinking, “You don’t count!” or snarkily remarks that “air travel is too expensive to take your wife!” to a chorus of chuckles, Peggy calmly refuses to react, but almost seems grateful to at last know what she’s dealing with. Behind the closed doors of the conference room, she’s no longer the same naive secretary who was buttered up and flirted with on the floor with the other “girls,” only to be insulted behind her back.

The meanness of “Mad Men” seems designed to echo the essential ruthlessness of high capitalism, where the powerful seek more power and the powerless are treated as nothing more than steppingstones or obstacles. Peter may be one of the best characters on this show for so painfully embodying this temptation to sell out anything and anyone for personal gain. This is a man who buys his wife a box of chocolates, then urges her to open it immediately so he can have one. Yet he’s a sympathetic character: The emotional void of his personal life propels his willingness to sell it for a price. More than his hardened older colleagues like Don or Roger, Peter is always casting about for someone to confide in, someone to talk to about what he’s feeling (or in some cases, not feeling). Like Betty, he can’t quite connect to anyone around him, yet he’s an emotional, sensitive person underneath that aggressively faux-chipper demeanor, one who desperately needs someone or something to keep him going from day to day. Peter subverts his neediness into a driving ambition at work, while Betty’s needs are slipping over into impatience and escapism.

There’s a sense of gathering gloom as this exceptional drama gains steam in its second season, a feeling that the individual and his or her high-minded goals and values will be dragged under by the wheels of industry and the restrictive norms of the culture, all in the name of modernity and progress. These characters have hopes and dreams of their own, but all are confronted with the same stern message: Check your emotions and your values at the door, and do what needs to be done. Or, as Roger himself puts it when Don protests an unscrupulous decision, “Oh, take off your dress. You get a chance at [a big corporate client], you take it! End of discussion.”

And so “Mad Men” serves up a message straight from a pristine time capsule, to remind us of the insidious gloom of boom times, and the messy catastrophe that underpins all that appears beautiful and modern on the surface: No crying in the break room! Now pull yourself together and get back to work.