Hacker News would never be, for me personally, on the top of the list of websites that inspire confidence by its looks, it's only when you delve into it and realise the content is actually great that you can appreciate it.
Such a shallow evaluation is quite strange coming from technical people who are used to mailing lists and all sorts of badly designed (or at least aesthetically unpleasing/neutral) pages...
The more something has been “designed”, the more the sight falls into the untrustworthy category, barring substantial evidence to the contrary.
Other than the whole unchangeable orange theme, I think it's fairly easy to intuit.
“Topcolor” setting on your profile page