She’s so petty for someone who won’t even admit she likes him. Tree Leaves treats the 3rd wheel all sweet and kind as if he's the most wonderful person in the world but treats Big Tree like an eyesore even though she realizes she's in love with him. I wouldn't mind if Big Tree dated Jiang Nan so we could see how Tree Leaves would react.
I get all this angst... I think blondie ain't that nice and she'll try to sway big tree with some guilt trip using her depressing situation. He's a kind boy and will try to help her, so in the meantime his relationship with tree leaves will take damage since she feels like she did something bad to blondie. And the cherry on top: there's also that upperclassman who's real cute and nice