And in one of my more shallow moments...
Whenever I am out and about in my eyeglasses (as opposed to wearing contact lenses), I will often remove them while I am walking about and only put them on if I need to read or see something up close. Keep in mind, without any form of vision correcting device between me and the world, the world becomes a hazy, blurry, faceless place. Sure, I can make out basic shapes and colors, and I can walk around without actually bumping into anything... at least not any more than I do when I can see perfectly well... but I can't make out faces more than two feet away from me to save my life. People become shapeless, moving blobs of color, lacking form, scale, and gender -- let alone any distinctive facial features.
For this reason, whenever I am without my glasses (and by that I mean whenever I am walking with my glasses in my hand or otherwise hidden away rather than on my face where they belong... which is whenever I am around people), I am always concerned that I may pass right by someone I know without any sort of acknowledgement or greeting whatsoever. Because I can't make anything else out, I tend to walk quickly, staring straight ahead, intentionally avoiding all risk for eye-to-eye contact. (Well, more accurately, risk for eye-to-blurry-blob contact.)
I'm always a little bit afraid that I will walk right on by a dear friend and hurt their feelings with my unintentional slight. As a Southerner in whom hospitality and cordiality are deeply ingrained, even towards those one may not much care for, but especially towards one's friends, this deeply concerns me. My vanity, however, wins out every time. You see, I hate the way I look in my glasses. The idea of someone I know seeing me wearing them (and especially the idea of a cute stranger who might otherwise turn out to be Mr. Right, but how could I ever know since he would never approach me in my glasses) concerns me even more than the idea of offending a friend. Politeness and social courtesy be damned. Somewhere out there is a cute, blobby stranger just waiting for me to run into him, and I can't be caught wearing my glasses. ...or maybe that's just another tree?