Why?
Their first meeting, without any prior encounters, Sun Jian hates her, probably because of Gong Yi.
Why?
Sun Jian thinks she bullied Gong Yi, so he plans to stand up for Gong Yi?
Qiao Chuchu glanced at Sun Jian, it seems... this man only looks decent on the outside, his intelligence isn't really impressive.
A truly wise man wouldn't behave like him.
She and Gong Yi are love rivals, from Gong Yi's perspective, Sun Jian should indeed dislike her. But... she's also Fu Ziqian's girlfriend. Sun Jian showing hostility toward her... would offend Fu Ziqian.
Fu Ziqian is his friend, Sun Jian discarded his friend for a woman.