Someone asked me, "What's up?" I looked up but didn't see anything. I said to him "I don't know. I don't see anything." and he walked away. What's up with that?
Seriously, that's how I responded the first time someone said "What's up?" Now I know it's a greeting, but what exactly does it mean? I mean are they saying "hi" or are they asking something like "how are you?" or are they asking "what have you been doing since you last seen me"?
Sometimes I hear people respond by saying "what's up?" back to the person so I think it's like saying hello. Other times, I hear people say "nothing much" which seems like they are asking what they've been doing.
What exactly does "what's up?" mean?
Sorry if it's a stupid question. I'm fairly smart but when it comes to social stuff I feel like I'm dumb and other people have told me they think I'm ret*d.