I finally got desperate enough to attack my hair with scissors. Didn't come out half bad. and no, I'm not brave enough to post a picture.
After yet another 'cut way too short' haircut a long time ago now, I stopped getting mine cut. I quickly worked out how to cut my own hair. It might not look like a layered cut, but it's ok, and I never did care about hair shape.
It helps if you have a mirror system which allows you to see both sides of your head reflected from another mirror. Mirror doors on cabinets are really good for getting the perspective better.
But once you figure it out, you wonder why we bought into the need for professional hairdressing in the first place. Especially when they never do it the way you ask them to.