Ron was always a jealous guy. He was very insecure when it came to other guy, especially when it came to you. Ron and you weren’t dating, actually you weren’t even aware he liked you. Everything was purely platonic between you two. Sometimes you’d make jokes, and he’d get flustered. But it was never enough for your to think or ever suspect that he had a think for you.
Yet here he was, watching you laugh and giggle with another guy. He hated it, he hated the way you smiled at someone else that wasn’t him. Of course he was too shy to ask you anything out right, and tell you how he felt out front. So he just let his feelings bubble up and spill over eventually.
So eventually you and him were just sitting in the common room, he was just doing something by himself while you were reading. " Hey Ron did you-" Before you could say anything, he slammed his hands on the ground and pushed himself up. " Do you ever stop talking? Why don’t you go talk to that guy you seemed to like so much?" He genuinely looked angry. Taking his jealously and anger out on you, despite feeling awful about what he said to you. He was still pretty mad at you, but he couldn’t really put all the blame on you. After all, he never made a move, or even tried to communicate how he felt about you.