"How are you?"

"gumballs!" is how I am.

How to answer? It depends. Who is asking? What is the context of that particular relationship? Did we just meet or have we been friends for years? Do we have an audience?  It depends on what aspects of my life -- the "you" in the question -- this person is actually asking about.

Aside from the part to do with me, I am faced with the need to quickly build a complex mental model of the asker, who I may have only just met. There's rarely time to do the person or the question justice before they follow up with the inevitable: "something wrong?"

Uhm.

It's hard to explain all this on the fly. I do try sometimes, especially with the cashiers at Trader Joe's, who seem very nice but I don't think quite follow my reasoning.

XKCD to the rescue! Now all I have to do is whip out my phone and point to this page, which explains everything.   Surely with this tool at my disposal there will be no more less confusion.