P
In a functional language, you have no guarantee that a simple function that should just crunch some numbers won't burn down your house, kidnap your dog and scratch your car with a potato while crunching those numbers.
In a functional language, you have no guarantee that a simple function that should just burn down your house, kidnap your dog and scratch your car with a potato won't crunch some numbers while burning down your house, kidnapping your dog and scratching your car with a potato.