From Primary School, all the way up to high school I had to wear uniform; and I hated it, but after a while it didn't bother me. When I went into year 10 at my college I no longer had to wear uniform, at least until my new head teacher came in and changed everything. At first it wasn't too bad, he implemented a dress code so that you couldn't reveal too much (No short-short, no short skirts, and bizarrely no visible shoulders but m'kay) but this didn't really affect me, being a guy im not exactly known to be wearing short-shorts or short-skirts for that matter, and I've never really been a tank-top kinda guy.
Then in Year 11 it all went tits-up. He introduced a school uniform for year 10's and 11's, but not 12 and up, so if i wanted to stay at the school (which I did) I needed to buy a WHOLE NEW SET of uniform to wear for not even an entire year. This change frustrated a LOT of parents, but the plans went ahead anyway, as his justification for it was "Well, its not a uniform for the Year 11's, its a 'dress code'" (What he really meant by 'dress code' was, "You just dont have to wear school branded uniform, but you still have to wear this, this and this. So it was effectively the school uniform, bar the school logos). He also gave a lot of BS reasons for implementing the change such as -
It will improve students learning
It will improve our neighbours respect for the school and its pupils
It will allow our students to look more formal (probably the only legit reason)
TL;DR All in all, I hate it.
EDIT: Uniform is also paper thin, so when its cold, everybody gets cold and complains
EDIT 2: The dress code also stated that clothing could NOT be skin-tight, and hair had to be of a natural colour, and not too long