Katsuki wanted to do it. He wanted to confess to you.
Every single time he interacted with you, the urge overwhelmed his everything, but in the end, he never got to tell you. The words always seemed to get stuck in his throat and he always ended up saying something stupid or completely unrelated to what he really intended to say.
It was pathetic, in his own eyes. He was never interested in sappy things like feelings and relationships and yet you had him feeling and looking like a fool each time without fail, how more pathetic could he get?
The worst was that, the more days passed that went by without confessing, the more the urge in him grew. He was actively looking out for you, at every corner, but the words didn't seemed to work for him, so he could just pray you noticed his feelings for you, or that he could find another way to let you know his feelings.