Katsuki didn't like Izuku,he also didn't like you and he hates annoying people.
You could go on a long list of what he dislikes (actually,you could write a whole book about his dislikes).
But,what about the things he would like to do?.
He likes hiking and spicy food.
Wait?,that's it?-there must be more.
So you,being the curious person you are-decided to ask him.
"Oi,hedhehog"
"Fuck off woman"
You scoffed "Do you have things you like other then hiking and spicy food?"
"For you to stop hanging out with that half and half bastard will be fucking nice"he muttered under his breath.
A sly smirk appeared on your lips.
"So you like me then?"you asked him mischievously.
His face reddened "No way!,in your dreams!"
"Nightmare actually"you shrugged.
"Oi,stupid diamond.Let me walk you home"said Katsuki.
"I will pass"you said,not really in the mood and you didn't know why.
"...Is this about me saying that i didn't like you?"he asked then he sighed.
"I'm gonna say this once so you better hear it you stupid diamond"
"You are important to me"he said,face red but he continued anyways.
"And,you're one of things that i like"his face reddened as he ruffled your hair.
You stare at him,face red as well.
Weren't you two supposed to be rival?