Kudos to Robert Weissberg on Minding the Campus for advocating more formal attire for professors.
I learned the hard way that I commanded greater respect from students when I stopped dressing casually on teaching days. I now get tons of “why are you so dressed up?” questions when I show up in a blazer, dress shirt, and tie — mostly from colleagues. It’s amazing how clothing expectations have changed over time.
I won’t even begin to discuss how students dress for class. I’ll let the commenters have fun with that.