Tipping is supposed to be for exceptional service.
For example, if the wait person takes your order and brings your food and nothing more I wouldn't tip.
If they do the above and keep your water glass filled constantly without need to ask, if your meal, drink orders and dessert come out promptly and correctly, if they ask if everything is ok throuought the meal at appropriate times, etc I would tip.
Getting good service is starting to get hard to find. Some waitstaff are really good some hate their job and really don't care about the experience you have at the establishment you are in. It's just a job.
Also I've worked in kitchens, I know what douche nozzles customers can be. That's when you can see who your best wait staff is. During times they have to deal with them.