And if the service is terrible they deserve a tip? Why is that?
Keep tipping places that do little to deserve it and they'll think they're doing a good enough job to deserve getting more tips. Some may even make it mandatory.
A lot of places elsewhere won't take tips that do a much better job than the lazy ass people in Canada, who tack on a mandatory tip to everything (karaoke, which most people see only before and after renting a room of which they paid for).