Personal comments about your appearance... What is a reasonable response?

[ChampagneTastes]

In the past two weeks I have had twice had my appearance commented on by strangers in public. I can't decide how I feel about it. Both comments were positive, both were made by men. One comment left me giggling like a teenager, the other left me feeling quite uncomfortable. I am now very confused.

When is it ok to pass comment on someone else's appearance? AIBU to say actually, it's never?

Commenting on a strangers arse saying you were looking at it is really creepy.

I have been dyeing my hair for years but a couple of months ago picked up the wrong box and ended up with deep purple hair. I wasn't bothered and would have gone back to "normal" except...I get endless comments on it. Actual random strangers have stopped me in the street, at events, shoppingand said "I love your hair/I love the colour of your hair."
And guess what? I love it!! Sod the patriarchy bollox, it makes me smile every time!
Someone phone work the other day and asked to speak to the woman with " the fabulous purple hair". I'm 50 and will take any compliment going - yes, even the "you've got great tits one" which is supposed to cause offence on here,, but made my day!

Wow, some people really do have a problem with people doing anything!