Having a choose a haircut, and then never ever ever changing it.
Look at photographs of the Royal Family. They seem to pick a hairstyle in their teens/ early twenties and then that's it. They don't even play around with colour. (I believe Lady Di's looks slightly different in photographs, but if you take into account hairstyles of the time, all the Royal Hairdressers were doing were slightly changing the cut to move with the times. She really didn't experiment with her 'do.)
And when was the last time you saw a Royal with blue hair (under the age of 70)????
I would hate to have the same haircut and colour I had 5 years ago. Hell, I'd hate to have the same haircut I had last year.
And that is why I shall never marry into the Royal Family (let's just forget the fact that I'll never be asked to marry a Royal. I'm making a stand people!!)
*I'm talking about the British Royals here. Living in one of their colonies pretty much means they're the only royal family we know about. (Other then the Danish one. But we only know about that one as Prince Frederick was awesome and married a Tasmanian. )Maybe other royal families are way cooler.