It's funny, but I grew up being told the standard tip was 15%. Supposedly Utah's are known for being lousy tippers. I try to make up for it by figuring 20% and then rounding up to the nearest whole dollar. I dislike built-in gratuities, so I always make sure the bill says 0% and leave cash on the table. If I ever went to an Appleby's the server would lose money on the deal.
