When an individual that has medium length or long hair and is just is out of ideas for how to style it then the perfect solution is the ponytail. It has many advantages such as keeping the hair off the face and looking neat and tidy without a lot of work.
Men don't want to advertise that they are asking for anything other than the "normal" cut when they visit the barbershop. It seems to be an unspoken rule, one that the barber knows very well. He knows exactly which celebrity hairstyle each man is quietly asking for and how to cut their hair accordingly.