I used to tip pretty good, and find at bars still do (continuous service throughout the night and want the good service to continue). Restaurants now though I tip 10% standard and 15% for exceptional service. If they are crappy I'll leave less than a $1 or so (just something so they know I didn't simply forget the tip).
It's weird how we are shammed into tipping now. Whenever I'm out with friends and we get bad service, I'm not tipping. It seems like even if we all get separate cheques so the server knows who didn't tip, my friends will still be slightly embarrassed.
And it is not that I'm cheap here, if we were throwing money into a pot to pay I wouldn't ask for my change back. I just find it principle.
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