I don't trust folks that dress nicely without having put in any effort into the rest of their look
Tell me more about why you don't trust these folks.  I'm not sure I understand.
I look down on people who do not know how to complete their looks when they are dressed nicely.
I think I see what you mean, but it is still rude to comment on other people's appearance.  Most people are just doing the best they can to look respectable, and might not share your keen fashion sense.  They might not even be able to afford all of the finishing touches.
Well, just think of an example: men who wear full suits, with shoes polished so well you can use it as a mirror.
I can see what you are asking me to imagine, and I don't think I fully understand what the problem is, but I imagine that there is something missing from the ensemble, that only someone with a sharp eye for fashion such as yourself would have noticed.  I have to reiterate, that even if this is the case, it is not a failing on their part.  Perhaps you could share your knowledge and give them advice?