keyofnik: It could be little more than a throwaway line, but I can’t help but wonder if Grandpa Hino is, in fact, Usagi’s favourite Grandpa because she doesn’t have her own grandparents. It could be that both Kenji and Ikuko’s parents are gone (or estranged), or it could be that Grandpa is Usagi’s favourite grandpa in the way that whatever food she’s eating at that exact moment is her favourite food ever.
