You've run into someone who's insane, really insane, or just far more intelligent than you. If nothing else, you're not going to listen because you can't or won't understand what's happening. But you can't stop them, either for reasons of etiquette and decorum, or simply because you can't get a word in edgewise.
If this is the case, all you can do is smile, nod, and wait for the other person to finish.
Compare Stepford Smiler.
- Yu-Gi-Oh! GX. Dimitri, a Duelist of the Week whose shtick is copying the decks and strategies of other players, is apparently convinced he's Yugi Muto when he steals Yugi's original deck and challenges Jaden with it.
Dimitri: That move takes me back to our duel against Seto Kaiba at Battle City. Those were some good times, weren't they old friend?
Syrus: Battle City? This guy's gone batty!
Chumley: Just smile and nod Sy, smile, and nod.
- Wizards of Waverly Place: The Movie. Alex can't understand the locals but uses a spell to create a literal caption floating in the air that translates for her. The locals talk about how she's a strange girl and maybe if they just smile and nod she'll go away.
- There's a movie called Just Smile And Nod.
- Played very sadly in Chaplin: Charlie has just gotten news that Hetty Kelly, the first girl he ever loved, died several years previously, and reels from the news, trying not to break down in tears. Moments later, his train pulls into the station and a huge crowd of fans is waiting on the platform. A friend asks "What do we do, Charlie?" and he replies simply "Smile," referring to the famous song to which he wrote the music. He then gets off the train and greets them all as if nothing's wrong.
- Dorothy Lamour sometimes found herself in this position whenever she shared scenes with Bing Crosby and Bob Hope in their Road to ... movies. Justified in that Crosby and Hope more often than not were off-script.
- Inglourious Basterds. The Basterds infiltrate a Nazi gathering with Von Hammersmark introducing them as an Italian film crew. When Colonel Landa comes up to them and starts speaking in fluent Italian, they can only respond like this. Landa finds their Paper-Thin Disguise a lot more amusing than they do, despite the smiles.
- This is the Archchancellor's stock reaction when Ponder Stibbons tries to explain anything to him. At least, when he's not confused by the metaphors. He's had to cut down on the habit, however, as Stibbons tends to play this to his advantage, which has resulted in Ridcully finding his signature in things he "agreed to".
- In Going Postal, Moist is a con man, and so demonstrates how good he is at this when some people who run the clacks go into technicals.
- Hurog: In Dragon Bones, Ward uses this while Obfuscating Stupidity, to pretend that he doesn't understand something someone tries to explain to him. He also causes this reaction in people, intentionally, at one point by explaining the exact difference between two different kinds of sheep. In great detail.
- Penny on The Big Bang Theory does this when the science jargon goes over her head (which is all the time).
- Doctor Who: Brought up as how to respond to the Doctor explaining something that makes no sense to... anyone else. Specifically in "Blink", Martha notes you should just nod when he takes a breath.
- Also brought up in The Fresh Prince of Bel-Air, when Will and Carlton are about to have a meeting with some record company executives:
Will: Now remember: agree with everything I say and disagree with everything they say.
Carlton: Why don't I just smile and nod?
Will: [beat] Even better.
- On Friends, there's a montage dedicated to moments where Joey does this, due to not understanding the other five's conversation.
- Used as a joke in the Mystery Science Theater 3000 episode The Horror of Party Beach, in reference to an Only Sane Man black maid:
Servo (as Eulabelle): Just smile at the stupid white people...
- In NUMB3RS, the FBI gang do this when Charlie explains some very complicated math theories.
- Sharpe: in Sharpe's Regiment, the titular hero ends up at dinner with Mad King George (the third, to be precise), who starts telling the tale of one of Sharpe's earlier adventures to his guests. One of the other gentlemen present kindly explains the situation:
Nobleman: He thinks he was there. Play along.
- In the first Sonny game, when Sonny and Veradux meet up with the paladin who's trying to take down Baron Brixius, the paladin mistakes them for two members of the three-soldier team meant to back him up (Sonny and Veradux killed them on the way to the paladin's location).
Veradux: Just shut up and nod, Sonny. Shut up and nod.
- In The Legend Of Heroes Trails Of Cold Steel II, when Sara suggests that the final free day is a good day for the students of Class VII to "get some ooh-la-la," the other students mock her as being as "shining counterexample" of this, given the time that she spends alone in her room drinking. Gaius eventually suggests that the polite thing to do would be to just smile and nod, but they continue anyway, Fie suggesting that Sara should just find some cats to snuggle up with if she keeps setting her sights on men like Laura's dad (a famed swordsman known as the Radiant Blademaster.)
- This is a general reaction to Hannelore from Questionable Content as shown here.
- This is regarded as standard policy for dealing with Brian from Rhapsodies when he's in full rant mode.
- In Latchkey Kingdom, when the dungeon rats give Willa a piece of unidentifiable garbage as a reward for slaying the Navi rip-off, the Interactive Narrator advises her to just smile and nod to avoid being rude.
- Referenced in "Have You Ever?" by Rhett & Link:
Have you ever not heard what someone said
So you asked them to repeat it again
But then the second time, you understood it even less
So you just smiled and nodded your head?
- The Penguins of Madagascar: One of Skipper's catchphrases. "Just smile and wave, boys," along with, "Cute and cuddly, boys, cute and cuddly." Also used in the first movie. The irony, of course, being that the penguins are more often than not the insane ones, and are deliberately invoking Cuteness Proximity to make people drop their guard around them.