Intrusive? Or Not Intrusive?

You're in the shopping mall, just walking and shopping (obviously).
Suddenly a stranger comes up to you and in a friendly manner, complimenting your complexion and then asking you "What do you use on your face ah?".
Would you consider that intrusive? Or not intrusive?

You're at Carrefour done with buying groceries and household necessities for mom.
And you're at the checkout counter, paying for your stuff.
While waiting for response from the credit card machine which happened to be extra slow that day...
Suddenly not one but TWO cashiers ask you "Ah Kak, you ada pakai apa 'kat muka?".
Followed by interrogation of the products I use... my hereditary (No, I repeat I'm not Japanese)...
Isn't that intrusive? Or not intrusive?

You're at the hair saloon getting your hair cut.
Hairdresser chit-chats with you and then...
You get the drift.

It's not that I'm selfish and refuse to share or anything. I know stuff. But it's not like I'm an expert in skincare or something. Neither do I claim to be one. And these are random people whom I don't know coming up to me out of nowhere and asking these questions.

My only reaction was lidah kelu, then politely answer their question and later my mind went completely blank. Didn't really enjoy these particular moments. Maybe it's just that I don't know how to handle this kind of confrontation without appearing too... oh I dunno... Miss Know-it-all? Or Miss Conceited.

BAH, how did people get so aggressive these days??

I feel like my privacy has been invaded. Period. But my friend doesn't seem to find anything wrong with it. She found it hilarious. Oh, tell me I'm just paranoid and overeacting. Argh.