When a practice such as the one George14 described is in place in a restaurant (socialism) what is the incentive to work hard? You're taxed on 8% of food sales no matter what, 1-3% goes to hired help, etc...
I suppose you're right, but I have to tell you that the service in my area has gotten so bad that we simply don't eat out very often.
A good waitstaff can make a meal with mediocre food a pleasant experience, and bad waitstaff can ruin a delicious meal. Maybe our local problem is that so many of the staff are high school students or recent grads. Probably still living with the folks, and not too worried about paying bills.
My experience has been that mature staff, the ones who count on tip income to pay the rent, bust their tails to make a meal enjoyable. Those people always get excellent tips from me.
It's the ones who don't care to acknowledge your existence that start off on a bad foot. If they're busy, I can understand that. How 'bout dropping by the table and saying, "We are so busy tonight and a little shorthanded, but I'm glad you're here. I promise to come by as quick as I can." So much better than someone pretending not to see you while you're trying to catch their eye.