What does it mean when a guy nods and smiles at you?

[Anonymous]

He already said hi. Maybe it means goodbye I'm busy I can't talk again? It was a upward head nod.

[Spencer10]

It means you are over thinking things! If you are analyzing a head nod which is usually nothing more than a polite acknowledgment.

[PasticheGrizzly]

It's a acknowledgment, like I see you and am acknowledging your presence. They do it to their guy friends all the time.

[Asker]

So he sees me as one of his guy friends? Guys don't nod at girls usually right, just to their guy friends.

[PasticheGrizzly]

Not necessarily, it could mean he's just friendly towards you. Which is a good sign.

[Omae_Wa_Mo_Shinderu]

It means, "What's good?" or, "What's up?"

[Anonymous]

It's a sign of respect.