Museums and talking etiquette

I was sitting on the bench in front of this painting this afternoon. I was letting my mind wander a little bit while doing so and was surprised to have my daydreams broken by a man who came from behind and asked if he could sit on the bench as well. I schooch over a little bit (unnecessarily, but it's an automatic response to a request like that) and get back to daydreaming. (Have I mentioned that I really, really like the museums in my city? They're wonderful and very rarely crowded. It's nice to be able to just sit for a while and not feel as if you are monopolizing a painting and preventing others from looking.) After some time, my benchmate asks if this is my favorite painting on display. I tell him that I really enjoy some of the paintings in the next room (Hudson River school landscapes... I'm such a sap), but that I do like this one very much as well, and I tend to stay a while if the bench is free and nobody else seems to be around.
I ask him about some of his favorites at the museum and he mentions a few pieces. I respond with approval (because the pieces he mentioned are very nice, indeed) and I return to daydreaming. Then, he gets up and says, "I have to get back to work, but it's been nice talking with you. You are fascinating. Would you like to continue this flirting session after work this evening?"

I was stunned and speechless for a couple of seconds because:
a) I wasn't flirting, I was just conversing
b) I was kind of miffed when he kept interrupting my daydream sessions
c) I sincerely thought it was just a nice conversation between museumgoers
d) I certainly wouldn't be flirting with a man who is wearing what looks to be a wedding band on his left hand

Extracting myself awkwardly from that situation and being accused by this man of leading him on, I am left with a few issues:

I'm not going to think about d) any longer. That's just incredibly unpleasant. Broadly, though, is every conversation that takes place between strangers just assumed by one party or another to be flirting? Should I have known that's what I was leading him to believe by answering his questions? I thought the questions about art preferences were serious questions about, well, preferences... do people just not ask those types of things without the intent of flirting? Am I the only one in the whole world who just has conversations with strangers without a thought to potential romantic involvement?

And most importantly,

When I am attempting to flirt it is completely ineffective and embarrassing but when I am not, apparently I'm "fascinating." What is wrong?

Yes, I know these are questions that need girlfriend attention. I'm out of those at the moment, so blogging will have to work, I suppose. ;)

And I really do like the Chase a lot.