We had the opposite: at our public school they were strict on uniforms, hair etc, which DS felt constricted his self-expression, and the strong focus on policing these arbitrary rules really rubbed him the wrong way! And I agree, who cares how long your hair is or what colour it is when you've got so much more going on *inside* your head?!
For many reasons we switched him to a private school, which had no uniform, and a reasonable and flexible hair and dress code, which DS was much happier with.
On a related note I have heard of a little gifted girl who would dress in theme every day - quite abstract themes! Like, she would dress as a season, or an emotion, or a place or a time. Tinsel in her hair would be giggles, and ribbons wrapped around her arms would be the tickling fingers, and her shirt would be yellow for happiness, or she'd wear clothes the colour of her house, with a grey beanie for the chimney and a green cape for the backyard and stick flowers in her shoes etc etc. So cool, but she quickly grew out of it when she started school
