As stated in ZUN's Undefined Fantastic Object music comments, Kogasa is a cheery happy youkai, but gets easily depressed when things don't go her way (which is very often), typically when she fails to surprise someone despite her best efforts. She stated she wishes for vengeance on humans for being discarded in Undefined Fantastic Object. However, she's actually quite friendly to humans and her vengeance doesn't go beyond surprising and spooking humans. She gets depressed when she fails spooking