Tipping: Obligatory or no?

From a thread at the Claire Files forums on whether tipping is mandatory or not. It seems that DullHawk's girlfriend doesn't like to tip, and after a few meals at the same restaurant, the manager asked them to either leave a tip for the server, or not come back (the GF was picking up the tab).

Good discussion going on tipping, from a libertarian perspective.

My response:

I wish more of our economy operated like the restaurant model--prices are reduced, so as not to pay for the service portion of the goods purchased (due to the owner's paying an absolute minimum, or none of, the service portion of his costs), and the customer gets to pay whatever he wants for the service portion, based on the quality of service he/she recieves. Imagine if the cable company, your mechanic, and your marriage were run like this...

(Well, maybe not your marriage...)

...then further imagine that the police departments, the DMV, and all local, state, and federal governmental departments operated this way. Hooboy, wouldn't that be fun!

That being said: I think you should tip. I usually tip using 15% as a baseline for average service; less for crappy service, more for outstanding service. It's not a gov't rule, just common courtesy.