It never ceases to amaze me how many people write these Yule Ball remakes (or any other canon rewrite) and have Harry literally come right out and tell Hermione, "I always thought of you as a sister, but then I saw you at the Yule Ball/looking hot and now I think I feel more for you than that."
Come on, you have got to be kidding me! Tons of people write variations on that confession and virtually none of them seem to realize that they are making Harry sound like the most shallow, insulting, insensitive male ever.
First it's insulting because he's pretty much saying flat out that he didn't think she was attractive before.
It's shallow because he spends every day with her, sharing all that time together, and then it took a dress and some makeup to get him interested in her romantically, rather than all the other traits that should have also attracted him, knowing her as well as he does. So obviously her looks had made a vastly large impression on him than all her other qualities combined.
Then it's insensitive and hurtful because those deep sibling ties he felt for her were, obviously, not very strong at all, if all it took for him to cast those feelings aside and see her, instead, in a romantic light, was for her to dress up a little.
It's ghastly and, quite possibly, more potentially hurtful than any of the crap canon Ron spewed at her after the Yule Ball, to spoil her evening.
How she could stand there and have him more or less say, "Normally you look so plain I don't even remotely harbor the kind of thoughts about you I'd have for a pretty, anatomically correct girl, and I thought of you more as a sibling, but then I saw how good you clean up and suddenly figured, 'Sister? Hell with that shit, maybe I should get me some of that action before Ron or Viktor move in on it.'" and not have the desire to slap him crosseyed before stomping off looking for Viktor, is beyond me.
His entire speech to her is ignorant, hurtful, uncouth, and oblivious to any semblance of propriety.
It boils down to, "Normally I wouldn't look twice at you, despite all the time we spend together, even when I was desperate for a date to the ball, but seeing you with your dress, makeup, and fixed hair, it's completely made me rethink our relationship."
It would almost be acceptable if he really did feel that way and decided to make an opportunistic play for her using some insincere speech, leaving out the parts where he pretty much craps all over her ego and the strength of their friendship.
At least then it could be suave and nuanced. Instead he comes out and proves his ignorance and insensitivity in the most ham-fisted and hurtful way possible.
"So let me get this straight... You thought I was your unattractive, nagging, older sister until you saw me dressed up a little, and decided to chuck whatever we already have in favor of possibly hooking up with me because I'm now perceived as Grade A meat? Whoa! Slow down, lover-boy, where did you learn such seductive poetry? You would have swept me right off my feet if I weren't so busy feeling hurt and insulted."
Guys, if you ever feel the need to confess your love to your long-time friend, leave out the part where, up until right that moment, you thought she was plain and sexually unexciting, to the point of feeling more like a gender neutral sister than an even potentially desirable female.
Leaving out the part where her suddenly appealing looks, rather than her personality and the relationship you share, were what made you ask her out... that would probably be a good idea too.