No food could touch. I would eat the hot dog and bun separately and eat the ketchup with a spoon. Pizza was the same: pile the pineapples, ham, cheese, spoon the sauce, and have the dough on the side. Of course all of them to be eaten in a certain order. The only reason why I have stopped now is due to the time it takes plus the odd looks.
As others have said, innate sense of justice and fairness with an attachment to rules.
Asking my mom how kids can play with each other on the playground. She gave me a script to use to introduce myself to other kids and ask to play with them. I was almost a teen when I stopped using this and it was only because it was the first time the script didn't work and I was devastated.
Similarly, asking my mom how to "wave arms while walking". Is it 45° angles back and forth? Same or opposite the legs? Elbows first for a sway or stiff arms?
Obsessively stacking and organizing objects as "play". Creamers in the basket at a diner, toys in a circle around me, trinkets in a row.
New media meant new characters to copy into my personality. From mannerisms to straight up copying the dialogue from the movie; I was a chameleon.
Pattern recognition is unparalleled to other in my grades. Still to this day, it's one of the traits that puts me ahead.
Flip flopping between "a joy to have in my class; my favourite student" for one teacher to "lacking in (basic neurotipical trait here), has a long way to go" for another teacher.