And then came this episode, and I loved everything about it. LOVED. IT.
The central premise of the entire episode is a call-back to a, like, ten-second joke from years ago. In the 2009 episode "Jerome is the New Black," Brian tricks Quagmire into going out to dinner with him by pretending that Cheryl Tiegs is the one issuing the invitation.
Little did Brian know, Cheryl Tiegs is Quagmire's great loss, the love of his life whose abandonment of Quagmire is an emotional wound he has been unable to heal. (In another episode, Quagmire blames their break-up on his subsequent sex addiction, but that seems like an unlikely rationalization.)
The payoff builds slowly here. In the first act, Lois sends Peter to pick up their dry cleaning, but he ends up starting a feud with the dry cleaner (a Chinese man known only to us as "Mister Washee Washee," and oh god I can barely bring myself to type that).
Peter ends up in jail. When Brian shows up to post bail, he meets a woman named Denise who seems to be perfect for him: she's ultra-liberal, passionately involved in several causes, and was arrested during an anti-WalMart demonstration. All the things Brian likes to pretend to be!
Unfortunately, she dumps him. To stop Brian from crying, Peter confesses that Quagmire has been teaching a class on pickup artistry. Brian signs up for the class, but he misunderstands its purpose, uses Quagmire's techniques on Denise, and loses her forever.
In the past, Brian has repeatedly tried to end their feud by ingratiating himself to Quagmire. But this time he decides to pour gasoline on the fire instead. This is a lot funnier than Brian's earlier attempts to pacify Quagmire, and let's be honest, he wasn't getting anywhere with that, anyway.
The episode builds to a point which feels inevitable: Brian and Cheryl Tiegs find themselves on a double date with Quagmire and Jillian.
One of the reasons the Brian/Quagmire feud is so fascinating is that both parties are essentially arguing with their own baggage. The feud has little to do with the differences (real or imagined) between Brian and Quagmire. It's about Brian's perpetual need to be liked, and Quagmire's need to find a scapegoat by externalizing all of his own worst qualities.
Once Brian and Quagmire start actually interacting with each other in a meaningful way, their pride pushes the petty bickering to a whole new level. But this also forces them to repeatedly confront each other, and by the end it seems that (even though Quagmire gets in the last blow) in a weird way they might finally have worked out their problems.
But even if it turns out they haven't buried the hatchet… Quagmire is SO in the right on this one.