Many think that these words were placed on the
shampoo bottle to encourage overuse of shampoo (thus making it neccesary to purchase larger quantities of the
product). This is, in fact, a
rumor. The
true purpose of these
words is to serve as a
defense mechanism if the
planet is ever taken over by
robots. As we all learned by watching
ST:TOS, if a robot is ever given an instruction, it will stop and execute it until
completion. If this instruction contains any sort of
logical paradox, the robot will
explode.
So, if robots ever try to take over the earth, tell them to wash their hair.