HOW LONG IS TOO LONG FOR FAKE NAILS THAT IS

I ask because I noticed a woman buying a subway fare card. It was very difficult as she tried to put her dollar into the fare machine. Her nails sooo long they were curled. As I stood in line to add fare to my card, I wondered how long was too long. There were only two machines working and the line was growing. People began to get very impatience. Someone shouted cut your damn nails. I just laughed at the time but later I wondered how long is too long. Weigh in