When I was in high school, it was deemed tacky to wear your prom hairstyle after the event. Even if prom fell on a Thursday, the unwritten rule was to take down your updo and wash your hair by homeroom that Friday morning.
My mom wasn't with it, though — she didn't spend all that money on a side bun and swoop for nothing! — and made me keep my style in for at least another week, much to my dissatisfaction. However, if I were able to rock an updo from Olivia Wilde's collection of styles, I would not complain. Have you seen her on the carpet before? Girl can werk a bun and ponytail.