As someone whose been in the hotel-restaurant-casino-bar industry for many years, to the best of my knowledge, 15% is still the standard/traditional tip for a party of 2 to 4 — and larger parties may have 18% added by the business. For a single person, a good tip might be 20% if the service is very good. Of course, that also depends on whether the total of the check is inflated by expensive bottles of wine or champagne — or a hefty bar tab.
But to tip more than 20% might imply very exceptional service, or some recent good luck (and a diner may have wanted to pay if forward and share with their generosity) — or a person may be exceptionally (and unusually) generous to begin with. Some servers have been known to be well-rewarded by someone who had wanted to impress the server with a big tip (for whatever reason, and despite the quality of the service).
And from personal experience, I know that no matter how good the service you provide, there are some people who just won't tip you at all, no matter how far you go beyond the call of duty. Rich people are especially notorious for stiffing food servers, bartenders and everyone else. Or sometimes they'll leave a very small tip to "send a message". The NFL's Eagles running back LeSean McCoy left an insulting 20¢ tip (not 20% tip) on a $61.00 meal.
The wealthy Beverly Hills actor/economist Ben Stein sometimes appears on Fox News to bash poor people. In July 2010 — when nearly 15 million Americans had been unemployed — this is what he had to say about unemployed Americans at his blog:
The people who have been laid off and cannot find work are generally people with poor work habits and poor personalities ... As I survey the ranks of those who are unemployed, I see people who have overbearing and unpleasant personalities and/or who do not know how to do a day’s work. They are people who create either little utility or negative utility on the job ... When employers are looking to lay off, they lay off the least productive or the most negative.
Ben Stein neglected to mention that for union workers, in-house seniority and/or time on the job usually determines who is laid off first — not those who wear too little deodorant or don't regularly brush their teeth.
Ben Stein recently dined at Craig's restaurant in West Hollywood. He said Senator Bernie Sanders only tipped 15% — and said Bernie should have tipped more. When asked by a TMZ reported how much Bernie should have tipped, Ben Stein claimed he always tips 30% (although, maybe not this day).
Ben Stein also said that back in the days when he and Hillary Clinton attended Yale, she had a reputation for being a little stingy (Now that, I believe.) But how would Ben Stein know what Bernie Sanders recently tipped for his meal at a restaurant? Does Ben Stein gossip with the waiters? (he seems to be the type.)
Or did the TMZ reporter (trying to get dirt on Bernie, to make "news") get that information from the waiter, and then later share it with Ben Stein to ask for his opinion? Or did Ben Stein (trying to get dirt on Bernie) ask the TMZ reporter to get that information for him? If so, some wealthy people have a lot of idle and meaningless time on their hands if they can be that petty.
Here's one article at the New York Times that says we shouldn't tip at all:
I’ve tipped slightly above the average for years, generally leaving 20 percent of the total, no matter what. According to one study, lots of people are just like me, sticking with a reasonable percentage through good nights and bad. And it doesn’t do us any good, because servers have no way of telling that we aren’t the hated type that leaves 10 percent of the pretax total, beverages excluded.
And then there's this from Vice News (October, 11, 2015) The Long, Uphill Fight to End Restaurant Tipping:
Over the last few years, a backlash against so-called "tipping culture" has begun brewing. But the custom of tipping at restaurants has less to do with culture than with economics. Restaurants are required to pay tipped employees only $2.13 an hour under federal law. (In some states, that number is slightly higher; in New York, it's around $5 an hour but soon going up to $7.50). This allow restaurants to essentially offload their front-of-house labor costs onto customers ... The powerful restaurant lobby (the National Restaurant Association) has spent millions convincing Congress to keep restaurant wages down. The last time the tipped minimum wage was raised was 1991. Almost no other country on earth separates tipped from non-tipped employees in this way ... Employment in the restaurant industry has grown by 80 percent since 1990, and because those workers are making less than the regular minimum wage, the country as a whole has lost spending power ... While the National Restaurant Association has argued that tipping incentivizes good service, restaurant customers are not necessarily logical in their tipping patterns. They tip more when paying with credit cards, less when they're part of large parties, and more when servers draw smiley faces on their checks. Whether the service was good only accounts for a 1 to 5 percent difference in tips, according to one study ...
Last July Senator Bernie Sanders introduced a bill (called The Pay Workers a Living Wage Act) for raising the federal minimum wage in phases to $15 by 2020 over 5 steps by increasing it to $9 in 2016, $10.50 in 2017, $12.00 in 2018, $13.50 in 2019, and $15 in 2020. After 2020, the minimum wage will be indexed to the median hourly wage. The tipped minimum wage will be gradually eliminated.
So eventually all food servers and bartenders would get paid $15 an hour, thanks to Bernie Sanders — and if Bernie leaves an additional 15% tip on top of that, is that so bad Mister Ben Stein? It's probably more than what the restaurant owners pay their employees: Owner of Red Lobster & Olive Garden Sued for Back Wages.
Robert Reich (October 2015): The Morality of a $15 Minimum Wage
Princeton University economist Alan Krueger pointed out recently in the New York Times that research suggests that a minimum wage set as high as $12 an hour will do more good than harm for low-wage workers. That’s because a higher minimum puts more money into the pockets of people who will spend it, mostly in the local economy. That spending encourages businesses to hire more workers. Across America, workers at fast-food and big-box retail establishments are striking for $15. Some cities are already moving toward this goal. Bernie Sanders is advocating it. A national movement is growing for a $15 an hour minimum. A full-time worker with two kids needs at least $30,135 a year to be safely out of poverty. That’s $15 an hour for a forty-hour workweek. Any amount below this usually requires government make up the shortfall – using tax payments from the rest of us to finance food stamps, Medicaid, housing assistance, and other kinds of help.
NBER (October 2015): How Does Declining Unionism Affect the American Middle Class and Intergenerational Mobility?
We find: 1) union workers are disproportionately in the middle-income group or above, and some reach middle-income status due to the union wage premium; 2) the offspring of union parents have higher incomes than the offspring of otherwise comparable non-union parents, especially when the parents are low-skilled; 3) offspring from communities with higher union density have higher average incomes relative to their parents compared to offspring from communities with lower union density. These findings show a strong, though not necessarily causal, link between unions, the middle class, and intergenerational mobility.