Socially awkward moment, I has it

I don't profess to have a lot of experience with randomly being hit on.
In my younger days, about 80 pounds ago and 18 years ago, I used to do the prowling.
Men loved me - mostly because I was hilarious and adventurous; qualities my husband holds near and dear.
But usually when I was hit on, it was by men old enough to be my dad, or men bored with their marriages (Danger! Danger! Stay away from those assholes).
Today, I decided to hop on the subway from Queen to Union because my left foot has been causing me some discomfort and walking up to work this morning proved painful.
I got on. Sat down. Adjusted my hair... and caught the eye of this man in a suit with his bag balanced on his lap. He was blonde, average, late 30s, glasses and he smiled at me. A genuine smile. Not a 'Hey, wanna buy a banana?' smile, but a friendly smile.
This threw me so I pretended not to notice and instead, stared real hard at this ad with a Christian message scrawled across it using signs ripped from TTC subway stations.
I actually found the ad clever so I snapped a picture of it.

When I glanced over at not old enough to be my dad guy, he was full-on smiling at me. A right up to his eyelids kind of grin.
Well, yeah, I just took a picture of a sign professing love of Jesus, so I'd stare too.
The train pulls into Union and I file off with everyone else and guy who is actually quite attractive, files in behind me up the escalator.
The crowd stalls at the turnstile and guy in the not a Sears suit leans in towards me and asks, "Is your sister so and so?"
Clever, I think.
"No," I reply. "You have me confused with someone else."
He smiles at me in a 'oops, my bad' kind of way and holds the door open for me into Union.
Honestly? I don't know what to make of any of this.
Not to appear to have a lack of self-confidence or self-esteem, but I haven't felt attractive in a long time and men generally ignore me. Except for men in furniture stores - they bloody love me. Oh, and men selling cars. I can get any hood popped - ask my husband.
So, wrapped in this moment of awkwardness and because I happen to be wearing a ring on my "married" finger (he was not, I looked), I asked him for his phone number. Let's cut to the chase, right?
He pauses, smiles, and asks, "How about a drink first?"
I'm usually swift and witty, but all of a sudden, I felt tremendously inadequate and inept. I hated myself for doubting he truly did mean what he asked, but I was overcome with a feeling of unworthiness and was dumbstruck by his question because I'm a married woman with no business drinking with any strange man.
"I'm sorry," I say. "But I can't do that. I'm not sure what this is, but I'm flattered. But I'm also married, and in a hurry, so I'll have to give my regrets."
Yes, I actually said that! Bringing it like it's 1890... right here, folks!
I didn't wait for him to answer. I walked away as confidently and as hurried as my busted foot could muster, and disappeared into the crowd.