I have always respected the leisure-heavy aesthetic of the flip flop. Wearing them clearly indicates you are not about to be doing any work or serious business anytime soon.
But this has to be weighed against the my-feet-are-getting-hella-dirty factor when it comes to urban flip flops. We have a shoe-friendly main floor of our house, so I always have a pair that act as summertime slippers. I have been known to wear them out to get coffee or brunch at a local spot on weekends. I will go home to change them if friends suggest heading out of the neighbourhood though...