"Immortality comes with many farewells." That was something Zhongli had learned after his many decades of existence. After the first few losses, he'd made a silent vow to not get too attached to any mortals...

~

"Mr. Zhongli!! Look at this cool rock I found!!" You exclaimed, smiling brightly as you ran up to him.

..unfortunately, it was quite hard for him to not find you endearing.