After embarrassing himself at work, Peter tries dropping some weight. While Brian suspects Lois is having an affair based on a racy story she wrote.
- Affably Evil: After using the horse to kick Brian, Stewie feeds and pets it.
- And Knowing Is Half the Battle: Parodied in the end with Chris addressing the audience about reading and libraries.
- Animals Hate Him: Brian gets kicked by a horse several times in the episode, although the last time caused by Stewie.
- Bait-and-Switch: When stuck on the stairs, Peter decides that he's going to do what James Franco did in 127 Hours. You think he's talking about cutting off his arm to save himself, but instead he calls up UCLA to have sex with girls not old enough to drink.
- Breaking the Fourth Wall: Struggling up the stairs, Peter says he somehow manages to do this every week during the theme song and tries to recreate that to make this easier. Also, he insists that Stewie says, "Effin' cry" instead of "Laugh and cry" during the song (which is a common point of contention among fans).
- Cruel to Be Kind: Quagmire only agrees to help on the condition that Peter does exactly whatever he says. When Peter starts lapsing during routine exercising and dieting, Quagmire traps Peter in his basement.
- Dramatic Irony:
- "Bri, Robot" actually did feature a quick gag of Lois cheating on Peter and avoiding being caught.
- While Lois absolutely insists in this episode that she wouldn't cheat, the newly thin Peter offers to sleep with Shelia.
- Embarrassing Browser History: When the sprinklers go off, it's shown that a slinky looked up a porn video and couldn't delete his browser history in time before he rusted.
- Everyone Has Standards: For all the times Lois has expressed being unhappy with her marriage to Peter (And certain incidents with Clinton, Anthony, Bieber, etc.), she's disgusted by Brian's stance about if she's cheating with him, it's okay but when he thought it was with someone else, he finds that and only that reprehensible.
- Humiliation Conga: Brian's attempts to use the story to seduce Lois result in publicly embarrassing himself, getting kicked by a horse several times, being called out by Lois, and Stewie arranging for a horse to kick him again.
- Hypocrite: Brian only tries to stop Lois from having an affair after attempting to seduce her (and reading her private writing to find this out, no less). She quickly calls him out on it.
- Laser-Guided Karma: After Lois shames him for his actions throughout this episode, Brian profusely apologizes and is unaware that Stewie is positioning a horse behind him. Stewie fires a rifle into the air to spook the horse into kicking Brian across the barn.
- Mistaken for Cheating: Surprisingly, it turns out Lois isn't having an affair this time. She was volunteering as a caretaker for a special-needs man.
- "The Reason You Suck" Speech: Lois easily dismantles everything Brian did in this episode as follows:
- He read her private writing without her permission.
- Tried to use said writing as a way to finally have sex with her by mimicking the supposed dream lover she made up.
- Objecting to Lois having an affair not because it would hurt Peter and the kids, but because Brian can't stand the idea of anyone but him trying to seduce Lois.
- And finally, bringing Stewie to stop her supposed affair, assuming he can't understand any of it.
- Running Gag: Brian getting kicked by a horse.
- Rock Bottom: Peter's struggles up the stairs and the millions of dollars in water damages he caused by pulling the fire alarm convince him he needs to lose weight.
- Self-Deprecation: Stuck in Quagmire's basement, Peter promises that whoever lets him out first gets a spin-off. He then quickly adds, "Not you, Cleveland."
- Take That!:
- Proof that the guy Brian thought Lois was sleeping with is learning-disabled (besides wearing a cape from a Darth Vader costume he had as a child and speaking in a Simpleton Voice) is his professed love of Coldplay.
- After Peter reveals his new slim yet saggy body and fat head, a guy drives by and shouts, "Hey, look! It's Jonah Hill sometimes!"
- Write What You Know: In-Universe example. Reading Lois's story as he and Brian go through the grocery store makes Stewie realize that she's writing about being there, and that the person "Louise" sleeps with is based on a real person.
