(Y'all, if something is more canon than headcanon, just ignore it. And this is just headcanon for my Yachi UwU)
1. Yachi keeps on unconsciously and accidentally flirting with people... And she doesn't realize it, and she's always confused when people blush around her.
2. Yachi is terrified of scary movies. And scary stuff in general. But she keeps on reading sad books.
3. Yachi always unconsciously finds herself touching other people, like their hair, back, nose, etc (no, not like inappropriately-)
4. And on that note, Yachi is a (mostly) innocent little girl.
5. Yachi loves children. Like she thinks they're adorable and cute.
6. Yachi reads a lot, and she's pretty smart, although she always says she isn't smart
(Lol that's all for now, this comes from many of my role plays XD)