It's all about communication. It's a given hairdresser has a different measuring instrument in their head than we do. Explicit communication must be used when communication with a person that has a pair of scissors in her hand.
So I walk into the salon where I am about to get my hair cut. Hair cutter person says "wow your hair has really grown". I say "I know thank heavens I can even get it in a short pony tail thingy". "But the sides don't seem to be growing as fast. Should WE shorten the back a bit so it could grow out together with the sides and it would be a short bob with some good layers"? "Sure" she says. "Let's go shampoo".
Friends I did not stress on the phrase A BIT!! I now have a very short back that matches up to the sides, it's cute but it's shorter than I wanted. But then again it's only hair and it will grow. We put a few hi-lites in it. I'll put my color on today. Then don my Easter bonnet tomorrow. Pardon me while I go look for my biotin.