Weird comment

So, yesterday, due to the fact that I hadn't washed my hair, I put it up in a ponytail. A regular, kinda messy ponytail. I went to work like that because, frankly, it was the most presentable I could look with dirty, undone hair. During work, I stopped by a coworker's desk. I never really see this coworker and he's about 70 or so and extremely messy all the time in appearance. I came by to ask him a question. The conversation went something like this (names have been changed):

"Sean," I said, "I have a quick question about your email."
Sean looks up from his computer at me. "Okay, sure. What's up?"
I ask Sean my question.
Sean responds, except, mid-sentence, he stops and says, "Hello!? Do you look different?"
Caught off gaurd by his interupption of himself I say, "What? Oh, yeah, well, my hair is back."
"Looks nice," he says.
I thank him and we continue our conversation. Then, I go to leave and he shouts after me, "It's nice to see you wearing your hair up for once."

What the heck? What does he mean by that? Isn't it usually supposed to be the opposite? Girls get complimented for wearing their hair down because they are too lazy to do their hair. I get complimented when I wear my hair back and messy when it's all greasy? Is this a hint? I look better with gross greasy hair pulled up than with the effort to put it down?

Weird...