If doing some simple math is so difficult, your phone has a calculator, or ask for a pen and paper.
I don't tip the checkout staff at the supermarket. Service is fine. I don't tip my accountant. Service is fine. I don't tip the car valet. Service is fine. I don't tip the waiter. Service is fine.
Why should the waiter provide poor service uniquely amongst all these untippes service providers?
If you experienced poor service in a non-tipping culture, it's not because the server knew there was no tip coming. It's because you had a bad server.
The evidences indicates that tipping does not improve service.
http://www.inc.com/jessica-stillman/psychology-agrees-with-d... ... and many more.
Especially in cultures where it's expected. I see people get awful service sometimes and then they tip. Tipping in restaurants in the US is not about service. It's about being able to pay employees below minimum wage and make them dance like monkeys to pay the rent.