As you can see, this picture shows why you should never mention or show anything related to parties to your pet Pinkie clones.
 
Back in the Pinkie Farm, the staff banned them from any form of partying, and forced them to become more “boring”. Buyers are warned not to mention anything with “parties”, for fear that any Pinkie clone who hears this will unleash all that “partying” she/he that was suppressed within her/him.
 
Many more lives were inspired afterwards.