I vividly recall my former Bethelite father curse when I was about twelve. The first I heard him curse. Being born-in, cursing was not a breach of etiquette but a certain trip to the ravages of Armageddon. We lived near a very bad urban ghetto. He loved going in to Manhattan b/c of his years at Brooklyn. We had scary adventures, major disputes with gun toting neighbors, etc. Never a curse.
During a routine trip to the grocery store, a long walk b/c we could not afford a car, he said "S....." about some spoiled fruit. He never regained his stature in my mind. His lectures and beatings about the WTS were not so potent b/c I knew a good Christian never curses. When the lions meet you to eat you, no cursing! It was one short burst and I never heard another curse word. But the Witnesses demand total perfection in humans. Perfection as in never doing anything wrong, even inadvertently. I later found that perfection in scripture means complete. Older English Books of Common Prayer use perfect rather than complete as a style matter.
This sort of funny q. reveals much about being a Witness. These stories are comical and sad at the same time. We were raised in Prude Central. Forget about your inner heart or actions. Look in the mirror as you read all the negative comments the NT uses to describe Pharisees. When I read about the actual Pharisees rather than the Jewish/Christian schism, Jesus is so much like one. He dined with them socially.