Christians are an embarrassment in public.
A non-Christian friend recently told me she used to work as a waitress in college. She said on Sundays there were always people there after church who would not leave a tip, because she shouldn't be working on Sunday. Of course, they always left gospel tracts...
So here are a few ethics I would consider minimal if you're a Christian and go to a restaurant:
- If you can't afford to leave a tip, you can't afford to eat out. Go to McDonald's or get take-out from KFC. Or even get one of those rotisserie chickens from the grocery store. But don't cheat the waiter.
- If you actually pray visibly and audibly in a restaurant (and I encourage that), you better tip heavily. I would suggest you tip 20% as a baseline. Terrible service is worth 15% if the waiter sees you praying, hears you talking about church or the Bible, or sees you in a tie at Sunday lunch.
- If you leave a gospel tract, tip a few dollars more. I knew a guy once who tipped at least $20 if he left a tract: that's not a percentage, and we weren't eating big---that's being more concerned about the Lord's reputation than his own wallet.
- You had better make sure you treat the waiter with respect: say "thank you" when he brings you your drink; say "please" when you ask her for a refill. And don't---whatever you do---don't ever make sarcastic quips. It's entiely possible the waiter is useless. It's possible it's the worst restaurant experience anyone ever had. But if you are publicly claiming to be Christian, you need to uphold a much higher standard. Complain to a manager if you like; better yet, complain to the waiter himself, but do so politely and calmly.
- Keep your kids under control.
It's in the little things that our Christianity is evaluated.