I hear this advice given quite a bit, but another perspective: I have never been pleased to receive a thank you email from a candidate. I do not want to receive something in my inbox that does not require me to act. It's a micro-annoyance, and if it's a bad day, I might have grumpy thoughts about the candidate being a brownnoser.
Show up to the interview clothed, be pleasant and polite, show off your game, and leave it at that.
Show up to the interview clothed, be pleasant and polite, show off your game, and leave it at that.