the.com/ingratitude
the art of receiving a kidney and complaining it didn't come gift-wrapped.
shakespeare's worstHe called it harsher than winter's wind in King Lear.
darwin's noteEven monkeys protest when peers get the better grape.
latin rootFrom ingratus, meaning unpleasing and unthankful both.
survival quirkBrains forget favors faster than they forget grudges.