Let's talk about dandruff

When did it become socially acceptable to point out physical flaws and deformities to strangers?
I know it's always been laudable to confront strangers about things they can change. But when it comes to things they can't, then it's just plain rude.
I remember once in 8th grade the 7th grade science teacher had her long skirt tucked into her panty line. It wasn't subtle either. A bunch of teachers were all standing in a circle talking, and it was clear no one was going to say anything. That is, except for Mr. Kenner, the somewhat inappropriate (though we could never put a finger on exactly how) drama teacher. He leaned in, and, without much pomp or circumstance, said, with full volume, "Honey, you've got your skirt tucked into your underwear."

I think that's nice.

On Saturday I stopped into a gas station to buy a soda and a kit kat. I'd just gotten my hair buzzed into a mohawk the day before. I always have a few problems in the days after such a haircut, namely, a dry scalp and tiny hairs that cling to my face and pillow. Anyway, I went up to the counter. At first I thought the cashier was going to flirt with me. His intro was, "How's it hanging?" Or some other shit like that. While he was ringing me up, he motions to his own head, and says to me, "You've got a little something in your hair."
Horrified, I grabbed both sides of my head to see if I could feel it.
"Nah, nah, left side of your head, here."
Slightly embarrassed, I say, "Oh, that's just a scar."
He follows: "No, not that. It's white stuff, or like something from outside, like..."
"DANDRUFF?" I practically shout.
"Dunno, maybe."
I frantically started to look around for something to find my reflection in, and the guy directs me to a sunglasses stand with the narrow little mirrors that you can never actually see anything in.
I go over, and I can't quite locate the dandruff flakes, or whatever it was, without my glasses. I sort of rub, as if I can see it, but I really can't. He tells me that I got it.

I walked out with my friend, reeling. She told me, "He was just flirting with you." Um, I know you can playfully jab at someone when flirting: "Hey you're short. Hey you smell funny. Hey your skirt is tucked into your underwear. " You DON'T tell them they have dandruff.

The thing is, I don't think he was flirting with me. I think half the time we think they are, they aren't. Maybe this is all coming off of seeing "He's Just Not That Into You." It comes off a high school and college career of never being able to tell if someone was flirting, or really just picking on me. Why should it be so hard to tell? At any rate, why do they have to be so mean? Because if they were nice, we wouldn't brood about it. We wouldn't even notice.

At any rate (as my mom would say), I've been checking for dandruff daily.