I agree with LisaE - the MYOB culture exists here on the surface, and in my experience, once people get to know you (however slightly) they think they can make very personal comments.
Case in point:
I walked into the staffroom the other day and someone said "Oh Vicky, I like that shirt you're wearing. Where did you get it?"
Me: "Thanks. I got it at Wallis."
Her: "Oh, so you're obviously a person that has more money than sense."
Me: "Thanks very much for that."
Her: (backpedalling, realising she's p****d me off a bit) "You've had your hair done too, haven't you? It that a new colour?"
Me: "Yes. I got it at Boots for £2.50 and I did it myself. Therefore, I had enough money left over to buy this shirt at Wallis." *Turns and walks away*
She's not someone I know very well, but rather a work colleague (and I haven't been there that long) whom I wouldn't really consider a friend, so I found her comments very surprising, to say the least.
I've also had people correct my speech and tell me I should stop speaking with my American accent.