A review of tonight's "Mad Men" coming up just as soon as I have two secretaries and three telephones...

"Jiminy Christmas. Think you're going to begin your life over and do it right. But what if you never get past the beginning again?" -Pete

The latter half of the run "Mad Men" has featured some of the series' most ambitious episodes, as well as some of its most satisfying. It's a more complex show than when it started, and frequently a better one. Yet I often hear complaints from fans who have grown weary of the show, and particularly about how Don keeps making the same mistakes time and again. It may be true to his character, they acknowledge, but if — to borrow Peggy Lee's question from last week's premiere — that's all there is, then why is the show still going? What's the point to it all?

The craft of the show has been so strong most of the time that I haven't been particularly bothered by Don's inability to grow. "New Business," though, was an episode so frustrating — and, with few exceptions, dull — that I could for once see that point of view.

Now, "New Business" was an episode specifically about how Don — like Roger, Pete, Harry and others — is trapped in a cycle of personal weakness and failure, and about Don's acute desire to escape that cycle. (Contrary to the title, he spends much of the hour dealing with old business, and failing to land the new relationship he wants.) He begins the episode looking at the first family he lost, and feeling an acute pain at realizing how well they've done without him. As soon as he gets home, he's greeted by a phone call from Rightfully Bitter Ex-Wife #2, and even when he gets Diana to come back to his apartment a second time, they wind up in the elevator with Arnie and Sylvia Rosen.

As he did before with Megan, Don decides that a woman he barely knows is the solution to all his problems. But Diana isn't nearly as simple as Megan was — or, rather, as Megan seemed at the time. She lost one child to the flu, and ran away from the other, and while Don Draper may be the man in New York best qualified to appreciate someone's need to run away from their problems and/or family, she's not buying whatever he's offering to her when he says he's "ready."

All of this material felt familiar while also trending more towards the feel of actual '60s melodrama — particularly whenever David Carbonara's score started to swell right as Don was drawing Diana into another embrace — than "Mad Men" does when it's at its best. We've seen this bit too often before on this show, done better, and without nearly as much of Megan and her family as we had to deal with here. 

Matthew Weiner can be brutal about cutting characters loose when he feels they've served their purpose (where have you gone, Sal Romano? a nation turns its lonely eyes to you), yet he's kept Megan around long past the point where she was adding anything to either our understanding of Don or the series as a whole. When I interviewed him before the season began, he said that Betty and Megan are different than Sal or Paul Kinsey because they're more important to our understanding of Don. (And Betty also provides continued access to Don's kids.) The problem is that Megan is such a flat and uninteresting character that she barely even fulfills the Don-related function Weiner's asking of her(*), let alone justifies being such a significant standalone part of one of our last remaining episodes. When Ken suddenly returned to prominence last week after being an afterthought for several seasons, it worked because his dilemma tied in so well to what everyone else was going through in the hour, but also because there remained aspects of his life that the show hadn't properly explored yet. Each time we cut to the Calvet women, whether alone or together, I found myself trying to imagine a less compelling use of the precious time the show has remaining.

(*) In that same interview, Weiner said he thinks viewers didn't like "Tomorrowland" — the episode where Don proposes to Megan out of the blue — because "They wanted him to go back to Betty." It was never that — not even for the small but vocal core of Betty fans — but that Megan barely felt like a character at this point, particularly in contrast to Dr. Faye, who seemed like a worthy and complicated love interest. Which, again, goes back to that common refrain about Don repeating his mistakes: choosing Faye would suggest Don had genuinely changed, whereas marrying Megan was Don trying to recapture what he had with Betty when they first met. And it worked out about as well. Don had a blind spot about Megan, but so does "Mad Men." 

Alan Sepinwall has been reviewing television since the mid-'90s, first for Tony Soprano's hometown paper, The Star-Ledger, and now for HitFix. His new book, "TV (The Book)" about the 100 greatest shows of all time, is available now. He can be reached at sepinwall@hitfix.com