As a server you are selling an experience, folks aren't just going out to eat.
People come back to relive a good experience. One of my favorite restaurant is Ritz Carlton in Fort Lauderdale the prices are high but it's the experience that makes you forget about the price and that is what you want to emulate as a server.
Your tables should be having fun. I remember when I went to Houston's on Atlantic our server always had funny little jokes that made our dinner most pleasurable.
He had been working at the location for close to 20 years and every time I go I make sure to request him. Something tells me he makes a good salary with his regulars....
When serving do just go through the motions... Try to make your guests laugh, relax have a good time, order another drink and boost your tip average for the night.
Even if they DONT tip well you want your guests to come back the YOUR RESTAURANT because this is how you pay your bills.
When a guests lets others know about a BAD experience at a restaurant they tell 10 friends when its a great experience they tell 3. Word of mouth is probably the most powerful form of advertising so please keep this in mind when having a bad day.