I'm notoriously dense when it comes to flirtation. I'd say that 95 percent of the time when a guy hits on me, I don't even notice. The other five percent, I know I'm being hit on because my friends have clued me in.
Sample conversation from a few years back:
Me: That guy really liked my shoes. He spent 20 minutes asking me where to find Chuck Taylors with racing stripes.
Friend: Huh? Shannon, guys don't care about shoes.
Me: But he asked lots of questions! And then he bought me a drink because I had such cool shoes!
Friend: He was hitting on you. Guys have nothing intelligent to say about women's footwear.
Me (realization slowly dawning): Oh.
So take this natural obliviousness, and throw in the fact that I'm in a relationship. On the rare occasions that I do realize I'm being hit on, I have absolutely no idea how to react. When I was married, it was really easy. There was a Diamond-Encrusted Man Deflector on my left hand that I could flash as necessary.
Here's an example: Friday evening, I was walking to a birthday happy hour. There was a light drizzle, but nothing major. A well-dressed, seemingly nice guy offered to share his umbrella with me. I declined at first, then we walked on together for about a block and a half. We were headed to different bars, so he offered to send me a review of where he was going (Ella's Pizza). Being old and wise now, I realized he was hitting me up for my contact info. I politely declined and moved on.
Afterwards, this bothered me immensely. I hate being rude to perfectly nice guys who chivalrously share their umbrellas. That sort of behavior should be rewarded. (Now, if he'd been a hyperaggressive little troll, I would have put him in his place with much joy and merriment).
Maybe I should have said, "Well, my boyfriend would think it was odd if I started getting pizza reviews from strange men." Then he'd know it was nothing personal. Or, "Get away from me, you foul incubus!" Just so I could assert myself. But I think my "thanks, but no thanks" reaction was probably for the best.
But give me SOME credit here. Five years ago, I would have thought this guy and I merely shared a common interest in pizza-centric happy hours.