"I hate shinobu!" Impossible. She's a smart, intelligent, legend, sweet, lovely, beautiful... Lady. Now about that bullying Giyuu part, she's not bullying him. She's teasing him. She says nobody likes you because she was mad that Giyuu protected Nezuko. As you can see in the manga of her backstory, she made a promise with Kanae that they will kill those demons. Also, not like Giyuu said he doesn't like her teasing. Gyomei has confirmed that they both are friends. Read more in description