In response to the "but they're comfortable" excuse:
Comfort may be a reason to buy something to wear in private (that explains why I own tapered Army sweatpants and three adult-size onesies), but it is NOT an acceptable justification for wearing said item in a public space, especially if that item is a pair of Crocs and you are a professional woman with dignity and at least 20/800 vision.
Imagine if you will the kind of world we'd have to live in if everyone wore whatever they wanted just because it was "more comfortable."
There would be pajama pants, fleece socks and bralessness in corporate meetings, there would be platform flip-flops, spandex shorts and oversized t-shirts on dates, there would be muscle tees and Mephisto sport sandals at happy hours, and eyebrow, leg, armpit, back and down-there hair growing wild and unkempt, peeking out of hemlines, necklines, waistlines and sleeves in every crowded subway car. If you think you're not having enough sex right now, just imagine how little you'd have if your boyfriend, wife or whomever felt (s)he had the right to dress, wax and tweeze however they - not society - deemed appropriate. He might be that one guy who listens with sincere interest about the people at your work and he may be that one guy who knows to calm you down with a pint of B&J Phish Food when you're acting like a demon-bitch three days before your period, hell, he may even be "the one," but I guarantee you if this soulmate of yours allowed a unibrow to settle above his nose-bridge, grew a T-shaped back-rug and decided to roll up to your best friend's wedding commando in his favorite Redskins-embroidered Zubaz pants, "Lickalotapus" hoodie and a pair of emerald green man-Crocs, your sex-drive would plummet about as quickly and extremely as Bill Clinton's does every time he hangs his head and walks in the front door.
You may think I'm going to the extreme end of extreme to prove my point, but frankly, I think Crocs are just as extreme in their offensiveness as any of the items I've enumerated above. Like denim stretch pants, Crocs are the quintessential example of a 100%-function-over-fashion item.
Look, I believe in indulging in ugly comfort when it comes to your own residence, but when I kiss my puppy's underbelly goodbye and cross that threshold into the no-longer-my-private-space public domain, the balance tips the other way --- as it should for everyone.
Where you fall in the fashion/function debate is up to you obviously, but just ask yourself this one question: what's more important, the comfort of an anti-microbial dishwasher-safe shoe and an extra $600 from not getting your hoo-hah Brazilianed for a year, or the confidence you gain from knowing you look your best and a sex life that consists of more than just the let's-both-look-to-the-side-and-get-this-over-with and the it's-your-birthday-so-I'll-allow-it-but-hurry-up positions?
Seems obvious to me.