I wore a suit when I interviewed at Reddit.

I didn't get the job.

(Vanity compels me to share: I was probably going to ask for more money than they would have been willing to pay. But before a former CEO pops in this thread to reveal that I was actually incompetent, I must say that I think I put on a good show. The weekend prior to being flown out to SF, I spent a day analysing their server code and was able to not only find a fairly subtle bug but propose a fix for it.)