note a few things. do ethnics really tip less, or do you notice when they don't tip right more than you notice white people not tipping right. do you serve mostly ethnic people?? maybe everybody tips horribly, but if you're seving mostly ethnics it would look like they do it more. be honest with yourself, do you give them the same respect you give white customers? if your line of thinking is that ethnic people tip less, i wonder if this affects the service that you provide to them. i've been in restaurants where a bouncy, upbeat, happy, smiley waiter will be that way at another table than come to mine with a lifeless "what do you want" sort of attitude. they may not realize it, and it may not be because i'm black, maybe they're having a bad day. without actual numbers, (the 90% sounds like a rough estimate) and without seeing you in action, we can't tell you YOU get tipped less from ethnic people, but to say that all of us tip poorly is slightly offensive. a behavior you see exhibited in some is being labeled behavior for all.