Are flip flops in the city in the summer a no-no—or not?

I love flip-flops as much, if not more, than the average person (I have 18 pairs, at last count), but I still feel like a dirty person when I wear them around the city (unless I'm going to get a pedicure, for which they are definitely required). I mean, New York City streets are filthy, and there's nothing more unsavory than that line of dirty sweat that forms along the edge of the rubber. Even though I always, always wash my feet before bed every night (my one OCD habit) it's not enough to counter-act what I've just put my toes through. But, I have my Working Girl tendencies, too, and nothing beats something that you can slip on and off as readily as Havianas. This is why I'm always on the hunt for simple, lightweight, easy-to-stow shoes that I can swap for heels when I get to work—and these espadrilles from Talbots, which just got reduced by 40%, definitely fit the bill (DISCLAIMER: these are a Lucky -wide obsession, as documented in this month's Style Spy). I think I might spring for them in Navy. Better for braving the subway than flip-flops, right?