Combination of actions developed over centuries by males who were tired of hearing and having to come up with responses to their girlfriends' incessant babble.
"And then like, oh my god, I got these cute grey and white shoes, they're so cute!! And next weekend, we're going to buy these black and white ones...."
-smiles and nods-
When some idiot is making no fucking sense, so you just smile and nod.
"Just smile and nod"
used to recommend the said action to someone else who is clueless as to what a third party is talking about. It is usually insulting to the first party.
Person 1: Oh man, the Teletubbies concert was rockin' last night!
Person 2: (silence, confusion)
Person 3: (to person 2) "Dude, just smile and nod."
Person 2: (Does so accordingly)
A very talented and hilarious improv comedy group from San Luis Obispo, CA
What are you doing next Saturday? Let's go to Smile and Nod!
Nod and Smile is also an accepted and sometimes prefered version of the phrase.
Take that Springy!
Springy: Dude it is so Smile and Nod! What the hell are you talking about with this whole Nod and Smile crap?!?
Feety: *nods and smiles*