Talk:Sans/In Battle/@comment-29580157-20161204215054/@comment-32125091-20170614100115

Maybe because, in Undertale, laughing is a mechanism for backing-off the pain. For example, Toriel smiles before she turns to dust. Snowdin villagers laugh away their sadness, example being Nacarat Jester that stands next to Scarf Mouse. Also, check Chara, that laughed away the pain when they and Asriel accidentaly poisoned Asgore.