In the US, good servers earn significantly more money under the tipping system than they would if the restaurant charged and paid more with little or no tipping. The good servers like it the way it is because their doing a good job results in them earning more money. Those who don't do a good job earn much less which makes the job much less attractive to them and (hopefully) encourages them to move on.

In non-tipping countries my experience is that it is a lot harder to get drink refills, etc. because the server isn't checking back on the table as frequently. (But that seemed to annoy someone earlier in the thread so I guess you can't win)