the level of service you receive from a high-end dining is light years ahead of what you get from a chain restaurant.
if you prefer to go to fast-food joints, that's cool. but if you go to a place and do not tip a certain percentage, then you deserve the ire of the staff and should get a good talking-to.
if you leave $6 on a $30 bill, that's 20%. if you leave that same $6 on a $300 bill, that's 2%.
if you think that is acceptable, then please stick to long john silver's.
If I may stick my massive nose into your conversation, I'd say that "It depends".
If that $300 Bill includes a consultation on a bottle (or two) of wine, appetizer, entree, dessert, and may dawdling over coffee....for 2 or 3 hours at the same table, I'd say that $60 bucks for a tip is pretty cheap. Figure that while you're sitting there...no one else is, so a tipping customer might be lost.
However, if that $300 covers an in-and-out meal and the service is lousy, well, then $6 might be a bit much. :-) Of course, I've not had too many in-and-out $300 meals, with lousy service. Maybe once or twice in NYC on business, that'd be all I could think of.
How so? The waiter gives me the menu, takes my order, gives me recommendations if I ask, brings me the food, checks up on me to make sure I am happy, and collects my payment. There's no difference between that from one restaurant to another.
Secondly, work is rewarded for results and efforts. So what if that 6 bucks = 2%? If the work is the same 6 bucks is 6 bucks.
Now what's all this about "deserve the ire" of the wait staff? Again such moralistic phrasing. The wait staff are not my moral judges, merely employees paid to serve me. Try to remember - "serve" is the root word of servant. They're servants, not judge, jury and executioner.