-- and make no mistake, I plan to someday -- here are the steps I'd require for the standard haircut:

1. Cut Hair:  obviously, this has to be good or nothing else matters. But let's assume it's an above-average haircut; then, IMHO, everything below makes it extraordinary.
   
2. Shampoo:  the scalp massaging part of the shampoo process is what big tips are made of.
   
3. Back-o'-the-Neck Shave:  using the clippers is not the same as using a straight razor to clean up the back of the neck.
   
4. Quick Eyebrow Maintenance:  if you don't appreciate this, you either naturally grow perfect eyebrows, or you are completely unaware of how bad your brows probably look. My favorite barber always spends 90 seconds making sure my eyebrows are under control.
   
5. Neck & Shoulder Massage:  I've had several barbers that have machines that give really good, brief shoulder massages. Most don't do it, but I think of it as the cool-down after a good workout.
   
6. Totally Gratuitous Touch-Up:  the barber that cut my hair this morning seemingly finished my cut, shaved clean the back of my neck, and then proceeded to grab the scissors again and clip away just a few stray hairs. Hopefully, they really were stray hairs and he was a perfectionist; but even if he wasn't, I bought into the illusion of his meticulous attention to detail.
   
7. Thorough Brush-Off: no matter how tight the tissue & cape are fastened, hair finds its way on to you: in your ears, on the collar or back of your shirt. I always appreciate the barber that takes a small broom-like brush or a leaf blower to my shoulders to whisk away pesky hairs. Powder optional.
   

I've had barbers that have done most of those things, but never one to rule over them all. A boy can dream...