Perhaps I am wrong but how someone dresses is extremely important and is a good way to judge their character.
No, it's an atrocious way to judge their character.
For example: rather unexciting attire for a female office worker in Australia would be outrageous in many Middle Eastern countries. That outrage is not a reflection of said woman's character or capabilities, but of the inability of those judging her to get past their irrational beliefs.
e.g You are invited to a wedding at a church so you turn up in t-shirt, shorts and thongs. Hmmm....
A wedding at a church is a formal event (and typically has a dress code specified on invitation, at that). Obviously wearing informal clothes is inappropriate. Even the typical filthy hippy would probably agree on that point.
Catching a plane, however, is not a formal event. Hasn't been for decades. In this century, it rates about as high on the formality scale as dinner at Sizzler.
I'm in my mid-30s. I generally wear shorts, T-shirts, and thongs or sandals most of the time (and
especially when flying), unless it's too cold or an event that deems more formal attire (say, work or dinner at a restaurant).
I do this because I dress for comfort and I live in Brisbane, a sub-tropical climate. Not because I'm lazy. Not because I'm a slob. Not because I want to "rebel". Not because I don't care (though, mostly, I really don't care).
Now, I grew up in the country and thus feel predisposed to judge people by their character rather than whether they're wearing thongs at the local cafe on a Sunday morning. But it's an argument I feel quite confident about being on the right side of. So when some stuffy old grump tries to tell me he's offended because I don't feel the need to get dressed up in a suit to do my grocery shopping, all I can do is shake my head at how someone can be so shallow.
) throw the first stones if my clothes aren't up to their preposterous standards 
- see serfty's post above which has a photo of us with drron in the shorts
