I used to be anti-flip flop as well. 5 years ago I got some before I went to Hawaii for my honeymoon.
On really hot days flip flops are much more comfortable than than shoes, socks etc. Not to work though, unless I'm working from home and need to walk the dogs or something. I am still opposed to men in leather sandals though.
Rhett, perhaps if your wife shaved her feet and hairy toes the appearance of her feet in flip flops would not be so offensive.