While I would want to be his b***h and build legos with him.
Just kidding, I wouldn't want to "be his b***h". I would want to be his goose instead.
Well... I would go on a sweet romantic date with him, where we build legos together.
On a serious note, I think those people, who make Seonghwa liking LEGOs seem like a bad thing, should go step on a lego and have their feet hurt for eternity.
I have experienced being made fun of for liking something and it wasn't fun at all.