And Another Thing

Two characters are in a room having a conversation. One of them makes to leave. But as this character reaches the door, he or she turns back to deliver a final line. Often this is some bit of exposition that sets up something later in the episode ("the starboard discombobulator's on the fritz") but that the writer couldn't figure out how to work into the scene's main conversation. In some shows there might be several lines of dialog between the two characters as the departing actor tries desperately not to look as though he's loitering in the doorway.

Just to mix things up a little bit, sometimes they'll do it the other way around: the character who remains in the room will call to the character who's leaving just as the latter reaches the door.

This trope is distinctly different from a good old-fashioned exit line, because the line itself isn't dramatic ("You can't fire me! I quit!") and is often in fact something of a non sequitur, which must be eased into with a phrase like "and another thing", "oh yeah", or "by the way."

Sometimes a character actually gets out the door, then comes back in to deliver a line, but this is usually for comedic effect. See Door Focus.

Not to be confused with And Another Thing, the sixth book in The Hitchhiker's Guide to the Galaxy trilogy.

Examples of And Another Thing include:

Film

Spoofed in A Shot in the Dark with the help of Door Focus: Clouseau leaves Dreyfus' office after an argument, the door closes behind him, and we hear "And another thing!" Since Clouseau doesn't know it closed, he turns around as he says this, points at Dreyfus -- and thus smashes the frosted glass window in the door. Embarrassed, he leaves without saying whatever that other thing was.
Maggie attempts this in The Great Race, but never gets to finish it as Hezekiah drags her from the tent. She does manage to get in a nice air-kick though.
A Catch Phrase of the Wiseman from Sucker Punch.

Literature

A Song of Ice and Fire: Tywin tells Tyrion, "You will not take the whore to court."
In The Moonstone, one of the Indians visits the offices of a couple barristers merely to form an excuse to ask one final question before leaving.
- In Armadale, Mr Pedgift senior does this all the time.

He invariably kept his strongest argument, or his boldest proposal, to the last, and invariably remembered it at the door (after previously taking his leave), as if it was a purely accidental consideration which had that instant occurred to him. Jocular friends, acquainted by previous experience with this form of proceeding, had given it the name of 'PedgiftsPostscript'.

Subverted in Men at Arms. Vimes, investigating an explosion at the Assassins' Guild, pulls an And Another Thing moment to try to get Dr. Cruces, the Guild leader, to admit there was a theft as well. Dr. Cruces, however, doesn't fall for it, and flatly states, "I never said anything was stolen." It's true, he didn't say anything was stolen, but that doesn't mean that nothing was stolen. The key Plot Device was stolen.

Live-Action TV

In A Game of Thrones Episode 10: "And one more thing. You will not take the whore to court."
Perfected by Lieutenant Columbo as a means of turning the screw on a suspect who is already exasperated by Columbo's shenanigans, since an Exasperated Perp is liable to make a Crucial Mistake. Though this became Columbo's most distinctive character trait, it started as a mistake. During the filming of the Columbo pilot, "Prescription Murder", Peter Falk simply forgot to deliver his last line before leaving the set, so he turned around, came back, and said "One more thing..." The take was left in, and became a defining moment.
Likewise, Detective Goren from Law & Order Criminal Intent, also uses And Another Thing in the same way as Columbo did.
The medical version (the "doorknob question") appeared in House: according to the writers (and presumably their medical consultants), many patients come in for a trivial ailment, and then bring up the "other thing" (probably the serious illness they actually want treatment for, but which embarrasses them) as they reach for the door knob.
Detective Flack did this once on CSI: NY. When he made to leave, the door gave him a Eureka Moment—he realised that the victim's door had been locked from the outside, so whoever killed him must have had a key.
Star Trek: The Next Generation often raised this to an art form, with whoever Picard was talking with in the ready room would say that one more thing at the door.
- And the reverse happens just as often, with Picard adding "one more thing" when whoever is in his ready room at the time is almost out the door, especially in the later seasons. In fact, near the end of the series, it's surprising to see anyone coming out of the ready room without Picard adding a comment.
Happened on The West Wing too many times to count. Often the plot of an episode relied on one or more of these moments.
Kellerman got a Crowning Moment of Awesome in his first case on Homicide: Life on the Street. Interviewing a suspected murderer/arsonist, he tells the suspect that they don't have much of a case beyond what he's already explained away, and that it looks like he's free to go. As the man is grabbing his coat, Kellerman asks, "Why'd you kill the dog?" The man's answer, "I didn't know the dog was there."
Frequently on NCIS, when Gibbs would visit Abby in her forensics lab and she would provide some information. Just as Gibbs is about to leave, Abby then chimes in with, "Wait, there's more," and provide another even more vital clue.
Done in the third episode of Sherlock. Jim Moriarty tells Watson and Holmes that he isn't going to kill them right now, and leaves, apparently taking his unseen sniper with him. Holmes runs to Watson and gets off the explosive jacket he is wearing, and everyone breathes a sigh of relief... until Moriarty walks back in, the little red dots of death return, and he says he's changed his mind and he can't let them leave after all.
In Torchwood, at the end of Episode 1, Season 2 right before John Hart leaves, he tells Jack "Oh yeah, I found Grey."

Theatre

The Women:

Little Mary: And another thing, I think this bathroom is perfectly ridiculous!

Video Games

The Legend of Zelda: Phantom Hourglass includes a pirate whom you fight on your ship at least twice. Every time you defeat her, she gives one of these lines - most of them quite lame and irrelevant.
Granin does this in Metal Gear Solid 3: Snake Eater. Snake is leaving, thinking he's done with the drunk scientist, but Granin stops him to give him a key and tells him which way to go.

Western Animation

This trope was parodied mercilessly on South Park with a scene that ended in four successive And Another Things.
Clone High did the same in in the premiere, as JFK kept coming back into the bathroom to reiterate the fact that Lincoln and Gandhi weren't invited to his party, and then because "I forgot to wash my hands!"
Uncle from Jackie Chan Adventures easily established "One more thing!" as one of his catchphrases by the end of his first scene in the series.
- In the French version, this is changed to "Je n'ai pas fini!" ("I'm not done yet!"), with similar results.
- Especially funny when the "one more thing" was to smack Jackie in the head.
  - In fact, there was one episode in which Tohru actually called him out on this. As a result, the master and the apprentice could no longer do their teamwork, and Tohru was kidnapped. When it happened, Uncle blamed himself while noting his tendency to overrepeat "one more thing" (not without saying "one more thing" before, of course) and whacking himself in the head repeatedly.
In Daria, Daria Morgendorffer's mother and her principal don't get along very well. When they end up in a tent alone together in one of the Class Trip episodes, it looks like they'll be at each other's throats immediately, but the show subverts expectations by showing them to have...a pleasant conversation. An awkward conversation, to be sure, but a pleasant one. Helen ends up (unintentionally) admitting her age and her insecurity about it, and that doesn't escape Ms. Li's notice when, moments later, the scene devolves into a shouting match. As Helen is turning to leave, Ms. Li stops her to say, "And by the way, you look fifty." Helen's mouth turns into an "O" of shock.
There was a Bugs Bunny cartoon where Bugs got a job as an organ grinder's monkey, managing to anger a gorilla in the process. When Bugs is done telling the gorilla off, he adds "And another thing...stop breathing on my cup!"
- Bob Clampett's Tortoise Wins By A Hare (1943) has Bugs disguised as an old timer trying to learn Cecil Turtle's method of beating the hare. His final line (indicating he knew it was Bugs all along): "Another thing...rabbits aren't very bright, either!"
In the Gargoyles episode "Turf", Angela has to tell the Trio off. While they were showing off and generally acting like idiots, the bad guys got away. She tells them that they have to focus on catching the bad guys, she is not a prize to be won, "And one more thing...STOP CALLING ME ANGIE!"
On The Simpsons, Nelson engages in Perp Sweating when he suspects Bart and Lisa of killing Martin. The whole thing is a spoof of Columbo, complete with Nelson engaging in an And Another Thing.
Conversed on In Treatment, where Mia has a tendency to say something important when she's about to leave.
She isn't leaving, but in The Emperors New Groove, Yzma finishes up a rant about how stupid and useless Kronk is with "And another thing! I never liked your spinach puffs! Never!" (This actually motivates Kronk to turn against her.)
In one of Tex Avery's George and Junior cartoons, George goes into a cave to lure out a chicken and instructs Junior to hit the first thing that comes out. He then turns around to say "And another thing"... and that's when Junior clobbers him.
During one episode of Metalocalypse, Dethklok walks in on a sadistic fashion designer skinning models alive. They can only stand there and scream. Except for Nathan, who makes sure to say:

Nathan Explosion: Oh, my god, what a horri- you're fired, by the way!

In the Family Guy Return of the Jedi spoof, Yoda continues to give dying gasps saying "Luke..." before sharing information before he finally dies.

Real Life

Steve Jobs' keynote presentations for Apple Inc. often ended in "one more thing" that didn't quite fit into the presentation itself. It was often cooler/more important than anything else he talked about.
Like Jobs, politicians often leave the "big" reveals until their end of speeches; for example, the 2011 UK budget left a cut in fuel duty until the very end of the budget. The end result is a noticeable "oh snap" moment among observers, including there at the speech and elsewhere, watching live. It also makes for prettier news coverage.
This is known as a "doorknob moment", where the very act of leaving prompts one party in the about-to-be-terminated conversation to offer information that had not come up, though it is more often the person who is not walking out the door that offers up new information.