That's the silliest way to judge people I've ever heard of.
Yeah, to be honest I agree with this.
In my case, for instance. I have a bad back. And a bad everything, really. Everything hurts all the time. Nerve & tendon issues, chronic... I go to physical therapy for this. But the shoes I wear are ones that were specifically chosen for me based on my therapist's recommendation. They provide the very specific sort of support I need in order to keep the pain at least somewhat lower.
In other words, theyr'e not a fashion choice. In fact, they're not really any sort of choice whatsoever. They are used because I need to. So they have literally nothing to do with "character" or anything of that nature. Just a simple necessity due to an uncontrollable physical problem. Anyone trying to get a first impression by my freaking shoes, will always get the wrong impression no matter what it may be. May as well try to get an impression of someone based on whether they wear glasses or not.
Definitely something that it'd be best to NOT do.
Now, that being said, can appearance be an indicator of personality? I do think so, but only to a degree. In my case, as I've mentioned elsewhere I'm male but rather look like a girl, and I have a giant keychain (like 3 feet long) that's often wrapped around my arm (easy way to carry it). I'm very clearly not "normal" right from the start, which absolutely extends to my personality. However, that's all that anyone could accurately get out of that. The amount of info you could get out of looking at someone is minimal at best.
Now as for myself, to answer the question... I dont really look at anything. Most people just look the same to me. I dont mean their faces, but stuff like clothing/style and whatever. All looks the same (unless I"m at a convention). Hell, even if someone doesnt really like "conforming" most clothing is designed that way by default, so it's very hard to avoid. So I dont form any sort of first impression simply based on looking at someone... the idea doesnt even occur to me. But I can understand why it occurs to others.