There's no denying that buns are the hairstyle you choose when you're generally busy getting your shit together. Your strands are up and out of your face, making it easier for you to deal with whatever the day throws at you like a boss. Ballet dancers get it. Fiction characters like Professor McGonagall and Mulan are on board. Even top female bosses know the power of the bun. But leave it to bad gal RiRi to spin that theory on its axis.