i'm fine with my physical appearance, for the most part. if i were answering this a few years ago, i would've said that i disliked my two front teeth, as they're a bit larger than the rest, giving me a rather "bugs bunny" look, but i've come to realise that they actually make my smile look more genuine.
but as i am answering this now, then i suppose that if given the chance to change anything about myself, it would be my hair. i don't hate it, per se, but when i was a child, my hair was curly and reminiscent of the hair of those statues portraying the greek gods and goddesses. however, since having my first pixie at age four, it's been straight (although slightly wavy) ever since. i'd personally want to get my curly hair back.