5. Gremlins
The Setup: Randall Peltzer finds the perfect last minute Christmas gift for his son, an adorable creature called a Mogwai that comes with a very specific set of instructions: don't expose it to bright light, don't get it wet and don't feed it after midnight.
What Goes Wrong: Randall's son Billy adores his present, dubbing the lovable little creature Gizmo. Given that 70% of the earth is comprised of water, making the 'do not get wet' rule fairly hard to follow, Billy douses Gizmo with a bit of water that causes Mogwai to spawn five adorable offspring. These little tykes don't stay adorable for long and soon break the 2nd rule by sneaking some food after midnight, turning them into hideous monsters who proceed to terrorize the entire town until Billy and his friends manage to explode them in a movie theatre. During the mayhem, in a particularly memorable monologue, Billy's friend, Kate, reveals the morbid reasons she has a die-hard aversion to Christmas: her father tried to come down the chimney dressed as Santa but slipped and broke his neck on the way down. This movie will make you question why you ever like Christmas in the first place.
The Moral of the Story: All this mayhem could have been prevented if Randall had conscientiously planned his holiday shopping in advance or if Billy had followed the instructions for his new gift to the letter but where would the fun in that be?