The reason why Amish grow beards but shave their mustaches is to represent their pacifism. The Amish associate mustaches with the military and thus they shave their mustaches to show they would never serve in warfare. The Amish who did serve did so in the Civilian Service Corps.
Researchers studied cats viewing photos of various bearded men. Cats viewing long beards exhibited paralysis and signs of severe neurological distress. Researchers concluded cats don’t like men with long beards, are indifferent to short beards, and disturbed/confused by incomplete beards.