All Just a Dream: Implied that the entire story is fake, one that a lawyer tells to convince a client not to divorce his wife. Part of it is that the lawyer has knowledge to events he couldn't possibly have known.
Berserk Button: See Eat the Dog below. Oliver was petty and childish in his half-hearted comebacks to Barbara, and he even tries to make peace after she nearly (and deliberately) kills him in his sauna, but that event was the turning point that made him every bit as destructive as she was.
Not to mention leading him to believe she has cooked his dog and fed it to him, at which point he pretty much goes ape shit.
Book Ends: The porcelain figurine that began Oliver and Barbara's relationship is the last thing that they fight over. It ends up smashed to bits by Oliver when Barbara refuses to hand it over to him, even when he was trading her everything else for it.
Closer to Earth: Played around with. It is shown that Oliver's overbearing and inaffectionate treatment of Barbara act as the starting fuse of the couple's bitter separation, by the point the two finally clash however, this has evolved Barbara into a vindictive and unhinged Bitch in Sheep's Clothing. Oliver, while still a rather unsympathetic self absorbed Jerkass, maintains some lingering amount of love and sympathy for Barbara even in his dying breath. Barbara, from a very early state, wants nothing more than the guy to just drop dead.
Cool Car: Oliver drives a classic convertible. Which Barbara destroys with her own Monster Truck.
Eat the Dog: Subverted. After Oliver accidentally runs over her cat, Barbara serves Oliver a pate and heavily implies to him that it's his dog, making him go mad with rage and grief. We see later the dog is alive, but Oliver never finds out.
Played horrifically straight in the novel, and the original intention was for the movie to follow suit. However, test audiences reacted badly so a very brief shot of the dog getting up was added to establish that it was still alive. Notice that other than this two-second shot, there's no indication in the rest of the film that the dog is actually still alive.
Oliver: (holding up one of Barbara's trinkets) Say it's mine, and you can have everything in this house.
Barbara: Okay. It's mine.
Falling Chandelier of Doom: At the end, they both hang *on* it, and then Kathleen Turner reveals that she loosened the screws to drop it on Michael Douglas. Chekhov's chandelier indeed.
The Film of the Book: Believe it or not, the movie was based on a novel of the same name. However, the original novel had none of the movie's humor and in fact got kinda creepy toward the end.
Footsie Under the Table: Done early in the movie, during a dinner at the Roses' house, by a female guest to Danny De Vito's character.
Framing Device: Danny DeVito, playing a divorce lawyer, tells a client the story of the Roses. He convinces his client NOT to divorce his wife. (A non-greedy lawyer? Wow.)
Grey and Grey Morality: Neither of the Roses is exactly an innocent in events; Barbara goes to extremely spiteful extremes regarding the divorce, but Oliver was a pretty controlling, dismissive and inattentive husband, all of which fuelled Barbara's resentment and poisoned the relationship.
Hoist by His Own Petard: Barbara spends quite some time and effort loosening the bolts supporting the enormous chandelier over the foyer. When she accidentally goes over the railing overlooking the hall, she ends up clinging to the chandelier herself. Oliver tries to help her by grabbing on to it, but it's too heavy and pulls him over the edge too. The combined weight is enough to send the chandelier crashing to the floor, killing them both.
I Ate What?: At the end of the book/movie, Barbara Rose makes dinner for Oliver, who compliments her paté. She says, "Don't thank me. Thank Benny." Benny is Oliver's dog.
Lack of Empathy: The pivot of the very venomous breakup. After Barbara shrewdly injures Oliver in sex games out of anger, he is convinced he is dying of a heart attack the following morning after it causes a hernia. Oliver recovers, only to find his wife is not the slightest bit mournful upon hearing of his supposed death (let alone that she indirectly caused it) and is now using his supposed dying will as a plan B to throw him out with literally everything to her name.
Know When to Fold 'Em: The Aesop delivered by Gavin to his client at the end of the movie, after the Rose couple subvert it to high heaven and refuse to let either gain winning ground up to their demise.
Murderous Thighs: Barbara Rose grabs her husband in a leg-lock when he's trying to get amorous, squeezing the breath out of him. The next day, the injury leads to a hernia, and results in Oliver believing he's having a fatal heart-attack... Which, apparently, inspires him to leave the house to Barbara as his "dying will." She immediately uses it as a legally-binding document against him.
It should be pointed out that Oliver's doctors tell him that his hernia could not have been caused by being "squeezed between someone's legs."
Pet the Dog: In the end, after they've fallen, chandelier and all, and they both lay dying in the wreckage, Oliver reaches out to his wife to show that he still loves her after all, and dies.
Kick the Dog: And Barbara, as her last act, grabs his hand and tosses it away.
Rape Is Love: Subverted. In their fight in the house where they are chasing each other around and breaking each other's stuff, Oliver tracks down Barbara and attempts to force himself on her. Immediately, she begins moaning as she did in their first sex scene. However, she only does this to make it easier for herself to perform a Groin Attack
This Is My Side: Oliver thinks it's a great idea to divide the house in "my rooms, her rooms, and neutral areas," even though it's clear Barbara is playing him for a fool. Gavin immediately tells him that it's the worst thing he could possibly do and advises him to move to a hotel ASAP.
Unrequited Love: Dead love example. Oliver still loves Barbara and amidst their horrific feud, still wants things to go back. However, Barbara wants Oliver out of her life in any way possible.
X Must Not Win: The driving point of the couple's war, eventually to their own detriment. They refuse to submit the house to the other, and slowly drive themselves insane with every petty attempt to destroy the other. Perhaps best exemplified with the Exact Words example above.