It may seem like you were dressed OK, but do you really know? Does anybody ever say "we can't hire that guy, he dressed up?"
If I were interviewing in finance, I would definitely wear a suit. If I were interviewing at a startup or a digital agency, or equivalent, I would wear smart trousers (maybe smart jeans) and a shirt. That's playing it safe. Sometimes I interview people who are wearing jeans and a t-shirt and generally look pretty scruffy - I know that they know that that is probably the attire most of their potential future colleagues will be wearing, but it certainly doesn't impress me much. But maybe I'm just old-fashioned.
I thought there was a lot of good advice in those slides, incidentally.
They're simply looking for someone who doesn't dress up because they believe that will indicate someone that they'd want to hire. You, as the applicant, may not be aware of this because there's often incomplete information on both sides of the table (that's what the interview is for). You can always ask indirectly, stop by their place and peek through the windows, or research this information yourself, like looking at company photos. Or you can just do what I do and dress up anyway because someone who believes that dressing up is a negative mark is probably not compatible with me.
It's come up a few times on HN that some companies do do this. They are widely regarded as completely nuts.
> When he walked in the door, we could hear the clacking of his shoes on our hardwood floor. He was dressed impeccably in a suit that probably cost more than my first car and was carrying one of those leathery-thingys that seemed to exist only for the purpose of being carried during interviews.
> I stole a glance to a few of the people from my team who had looked up when he walked in. I could sense the disappointment.
> We’re all happily wearing blue jeans and sneakers. It’s not that we’re so petty or strict about the dress code that we are going to disqualify him for not following an unwritten rule, but we know empirically that people who come in dressed in suits rarely work out well for our team.
> He was failing the go-out-for-a-beer test and he didn’t even know it.
http://web.archive.org/web/20140618142018/http://blog.42floo...