Yeah, it's not nice... Your mind goes haywire when you can't follow your schedule, you see. Tsk, definitely petty.
Im somewhat the same, i always get worried I'd be late if i dont follow my schedule even tho i know clearly well that i dont have to be because i always get to school early. One time i woke up late but not late enough that i wont make it to school but even so i skipped my breakfast just to leave the house at the exact time like how i usually do. So yeah its pretty annoying when you cant follow the specific time/things you have planned. But once im in school i dont really have a schedule since there's a lot going on.
He’s got a strict schedule he follows. I wonder if it’s just a trait of his or it’s something he has to do or he doesn’t feel right. I had a friend like this once. They take 30 minutes to arrange their school materials and writes incredibly neat. They also couldn’t play a video game without having the time stamp saved to either 0 or 5. They had a watch so they save at the ‘right time’. I didn’t really understand it at the time but I knew enough to understand it means a lot to them. There’s an entire routine they need to do or else they feel anxious. Scratches themselves and bite their nails if they can’t do it. Last I heard they tried seeking help.
If Sangwoo is anything like my friend (which I doubt but you never know), I don’t think it’s nice of Jaeyoung to ruin this guy’s schedule. It just makes him petty.