There was an article I recall reading back when Laura Bush was Flotus, and a bunch of the best, smartest college senior girls had lunch with her to pick up some award at the White House. In the official picture most of the girls wore flip flops.
The article commented the girls mothers were appalled, their daughters felt there was nothing wrong with that.
I remember when I got an award in college from then governor Florio, that day I had gone to the beauty parlor to have my hair and nails and makeup done professionally, and bought a dress that sent me back a couple hundred at Bloomies. Bought a pair of heels. I had to go into my savings and it was so much money at the time but it was a huge honor and it was a "formal" awards dinner.
At least I got to use the dress for a couple of weddings too.