I am really grossed out by long bootcut jeans, left really long so that several inches drag underfoot and get all mangy, shredded, and disgusting. Sometimes they are so long that the wearer has split up the side, at the seam, to allow the leg opening to open up (if that makes sense). They usually look like they haven't ever seen the inside of a washing machine. I see this look a lot at the grocery store, usually with flip flops or Ugg-like boots, on young women and men (I live in a university town).
More generally, I think bad hair contributes to someone looking less than polished (I realize that bad hair is somewhat subjective!), and wearing really ill-fitting or dated clothes/shoes. Also, too much make-up and over-tweezed eyebrows, for women.
I feel like I should add that I have lots of work colleagues who really don't care about fashion or style; it's just not what they focus on. But when I look at them I don't think "She is so unpolished"; instead I see a fab colleague who is just herself, if that makes sense. People prioritize different things, and I totally respect that.