Shangguan Hao hastened his departure not because he had urgent matters to attend to, but because he did not want to give Yang Xiao the chance to refuse him.
After all, in his mind, there was a good possibility that Yang Xiao would reject his invitation, so he couldn't let Yang Xiao utter a word of refusal.
As long as Yang Xiao didn't voice his refusal, it could be taken as if he had accepted the invitation.
Anyway, he had made up his mind to befriend Yang Xiao, to become his brother.
Even though he now had some understanding of Yang Xiao and knew that Yang Xiao didn't have any particularly unfathomable background, it did not deter Shangguan Hao from wanting to be friends.
In fact, for Shangguan Hao, this was even better; in associating with Yang Xiao, he didn't need to have any ulterior motives—he would simply regard Yang Xiao as a friend.
Moreover, for someone like Yang Xiao, background didn't really matter; he was his own background.