I notice that all the contributors so far to this thread are Americans. Is this a peculiarly American topic ( I suspect that the anti-tie attitude is more frequent in the USA), or does one encounter such comments across the whole western world? I wear jacket and tie for about half the time, and noone has ever said "what are you dressed up for?" though I have had the occasional comment "you look smart".
I never received any comments on my clothes in Russia. No one stared, and no one ever said anything about my clothes--and I was wearing full head-to-toe vintage. Here in Idaho I get a long stare or a comment at least once a day.