Jassi! Give us 10 Ryuji facts (or head canons) we dont know! Go go go!!
Oh gosh, no pressure! But I’ll do my best here!
I can see the sport of soccer appealing to him a lot - it’s another sport that involves a lot of running and kicking - a perfect opportunity to strengthen your legs and build up your stamina through all that running. Maybe even learn precision if you’re the goalie. I like to think he tried out soccer before deciding to go with track and field because above all, running is what most appealed to him.
I like to think he has a surprisingly extensive knowledge when it comes to sports injuries. Not only from enduring one of his own but also through experience - he’s learned through trial and error, so he usually has pretty decent advice to offer if someone is struggling with an injury or a sports related issue of their own.
Given his experience with having an abusive deadbeat dad and Kamoshida, he’s pretty wary around adult males in positions of authority. He just sort of naturally distrusts them and finds it easy to assume the worst from them because the two primary figures in his life have treated him like shit. He’s more or less indifferent when it comes to women - it depends on how they treat him as an individual.
I like to think that his interest in manga really picked up after his injury - having to spend so many times either sitting down or taking it easy, he quickly became bored and tried to find something to occupy his imagination. Manga became a natural fit and by extension, an escape of sorts. Sure, he was into it as a kid but not nearly to the extent that he is now.
He’s pretty hopeless when it comes to dealing with computers - he can handle a phone and a video game console decently enough but something about computers just utterly puzzles him. If he has the option to, he’ll happily seek out one of his more tech savvy friends for help.
I think a lot of people would expect him to prefer things that are really sugary and sweet but that only really extends to his coffee - because he finds the taste of coffee to be bland and pain. As far as sweets go, he more leans towards treats that are salty or bitter. Too much sugar can be a bit much for him.
He knows it’s not the healthiest but he can’t resist downing a big bottle of soda every now and again - even better if he can show off how quickly he drink it. He almost always feels sick afterwards though.
I’ve always seen him having a certain awe and respect for Makoto for a number of reasons - a) she’s an upperclassman and the student body president, b) she’s one of the most badass fighters out of all of the Phantom Thieves and c) she can be intimidating as heck sometimes. She is one person he does not want to piss off.
On a different note, he has a certain affection and protectiveness when it comes to Haru - given that she was one of the Thieves who arguably suffered the most, through no fault of her own. She’s just a really sweet and nice person at her core and he hates seeing nice people have to go through so much unwarranted shit.
Outside of shipping, I would say his relationships with Futaba and Yusuke are pretty similar - he’s protective of them but in a different way from Haru. He views them as little siblings and tries to take it upon himself to show them more of the outside world and maybe even try to broaden their horizons a bit. Sure, sometimes he finds their quirks a little odd but if anyone ever tried to belittle or shame them for it, that person had better start running - and fast.