I know there are probably some people in the service industry who feel very strongly about the subject of tipping.
As a customer, I have always understood that tipping is expected and appreciated, but not obligatory and certainly not mandatory. Some workers are not allowed to accept tips, others expects them regardless of their actual salary.
IMHO, I don't think you should expect a tip for doing your actual job. I understand the idea of a minimum tip to augment servers being underpaid, and I have no problem being generous - when I go to restaurants I consider my bill payment for the food and not having to cook said food for myself, and then the tip is my payment to the waitperson for waiting on me. I don't know why we tip waitstaff but not the cooks or busboys or any other employees in a restaurant?
If I feel my server has gone above and beyond, I will leave a bigger tip to show I appreciated it - I feel like they "earned" it. Lets face it - any job where you have to deal with people and schlep for them is challenging at best. Workers can be rude, but so can customers.
I will confess I have never left a small tip, or no tip. This is not necessarily because I am nice, I am often just lazy. I don't want to do the math.

I've never gotten service that was so bad that I didn't want to tip (maybe I'm lucky, maybe I'm just really laid back

) - if I ever did, I would be speaking to the server and/or manager and giving them a chance to rectify the situation before I decided whether it affected my payment.
I don't really have an ehell worthy stories about a server who lost their tip because of their behavior. Not all dining problems are a server's fault. Maybe the kitchen is to blame. If a server managed to really tick me off, their tip would be the least of their problems - I would complain to their manager and factor it in when deciding to ever spend money at that restaurant in the future.
I think servers today should worry more about their behavior being reported on places like Yelp, than about how much of a tip they were left. Poor service can have farther-reaching consequences, as the "I'm never going there again" thread reminds us.