he keeps doing things to make Kana-chan happy and that makes Serita happy, he also says and does things that surprise and shock Serita, things that she thinks are embarrassing, but aren't meant that way, Yukiji will sometimes blurt out words without thinking how they can be taken, his nee-chan is pushing him to get closer to Serita, she doesn't want him to be like her and be lonely after getting out of college.