If you're famous for being worth $20 billion, then you can understand why restaurant serving staff may be a bit hopeful when you show up for lunch. However, staff were left reeling when Mark Zuckerberg, the founder of Facebook, left after a recent meal with his wife Priscilla Chan, without leaving a tip.
And he's not the only one ever to have made a poor tipping decision.
Zuckerberg was said to have spent €32 on lunch in Rome's Jewish Ghetto quarter while on honeymoon. He reportedly rejected wine in favour of water, and opted for local specialities including deep fried artichokes.
The restaurant owner told a local newspaper he was shocked, as Zuckerberg had said he had enjoyed the meal, and he assumed Americans were culturally more likely to tip. There are other reports that he took a similar approach the previous night.
There's every chance he was following the 'when in Rome...' approach, and misjudged expectations. However, he's far from the only one to get it wrong.
Last summer he almost eclipsed the rioting with his decision not to tip at an Italian cafe after ordering two cappuccinos. He eventually returned to the cafe, bought two drinks for €5.10 and told waitress Francesca Ariani to keep the change from a 10 euro note. Lucky for him the breakdown of law and order back home took the heat off a bit.
He is a regular fixture on lists of poor tippers, which is a shocker given that he is said to be worth $500 million. He claims it is because he never carries cash.
The Entourage actor was said to have left a DVD of the show in place of a tip after one mega-bucks dinner.
The pop star of yesteryear is said to have once left his autograph as a tip - which sadly isn't going to raise that much cash any more.
When the American Football star left a $200 tip at a restaurant in March this year, he was doing the decent thing. Unfortunately for his waiter, however, the decision to post the receipt online got him the sack.
In the world of the celebrity tipper, they could stand to learn something from Johnny Depp. He apparently went out to celebrate a screening of Public Enemies with a group of 14 friends. The restaurant did them the favour of staying open until 2.30am, and were rewarded with a $4,000 tip.
10 of the weirdest celebrity products
Mark Zuckerberg left no tip: other poor tipping decisions
When it comes to bizarre celebrity products, they don't come much weirder than the Bill Wyman Signature Metal Detector, designed and marketed by the former Rolling Stones bass guitarist.
Apparently, Wyman, who is now in his mid-70s, loves archaeology and has used his own metal detector to find relics in the English countryside dating back to the Roman Empire.
Fans of US president Barack Obama can show their appreciation for the politician by buying a Barack Obama Chia - shaped like the president's head - and growing grass out of the top of it.
And for those who prefer a more historical theme to their garden ornaments, Chias shaped like the heads of George Washington and Abraham Lincoln are also available.
Action star Sylvester Stallone put out a protein-infused pudding designed to appeal to fans keen to build muscles like the big man's.
Unfortunately for them, however, the pudding has now been taken off the market.
Heiress Paris Hilton endorses numerous products, ranging from outfits for your dog to hair extensions.
But the most random Paris Hilton product on the market has to be her line of craft supplies, the Creativity Collection, which features items such as stickers and transfers.
Rapper Snoop Dogg's latest business venture is a "smokeable" lyric book.
"Rolling Words: A Smokable Songbook" contains the words to some of Snoop's biggest hits, including "Ain't Nothing But A G'Thang" and "Gin and Juice" - all on cigarette rolling papers.
Hollywood film director David Lynch loves coffee so, of course, he decided to make his own.
Embarrassingly, the tagline on the David Lynch Signature Cup is "It's all in the beans ... and I'm just full of beans."
Former boxer George Foreman's grill is undoubtedly the most successful, random celebrity product of recent years.
The "machine", which claims to reduce the fat content of your meal by 42%, has earned Foreman more than $200 million over the last decade or so.
Supermodel Heidi Klum has her own line of low-fat sweets, which includes Heidi's Yogurt Dessert Cremes and Heidi's Yogurt Fruit Cremes.
Apparently, the design of the sweets is influenced by icons that Klum uses in her text messages to friends. Strange.
Actor Danny DeVito is such a big fan of Italian liquer Limoncello, he decided to launch one of his own.
Called Danny DeVito's Premium Limoncello, the diminutive star claims that it's "like pouring yourself a glass of liquid sunshine straight from Italy's Sorrentine Peninsula".
Steven Seagal made his name leaping around in action films that allowed him to show off his martial arts prowess. But he is also behind an energy drink called Lightning Bolt.
Advertised as being "packed with vitamins and exotic botanicals", it sounds like just the tipple if you are planning to take on 10 armed men with your bare hands.