Can we dispel the myth of tech companies as being super lax when it comes to attire? (Presuming this is a tech company since you asked on HN and mentioned programming). The last thing I would wear to an interview is something casual and slacker. You want to give the impression that you've come there to work hard, so at least make the effort. If you wear the same hoodie you've been wearing since you were 12, you will be immediately cast off as incompetent. Make an effort.