Renowned aerobatic pilots Sean D. Tucker, flying the Oracle Challenger III, and Jeff Boerboon, flying the Jack Link's Screamin' Sasquatch, take to the skies over EAA's 2015 AirVenture Oshkosh, on Monday, July 20, 2015 in Oshkosh, Wis. (Photo by Matt Ludtke/AP Images for Jack Link's)

Dynam employees say a greeting message as they receive customer-care training ahead of the grand opening of the company's pachinko parlour in Fukaya, north of Tokyo July 29, 2014. Japan's once-booming pachinko industry, grappling with a greying customer base and the threat of new competition from casinos, is adopting a softer touch and smoke-free zones to lure a new generation of players, particularly women. Pachinko, a modified version of pinball, is a fading national obsession, with about 12,000 parlours nation-wide and one in thirteen people playing the game. But that figure is declining as the population shrinks and younger people prefer games on their mobile phones. (Photo by Issei Kato/Reuters)

People ride a prototype of a driverless vehicle as it is moves through a pedestrian area in Greenwich, east London, February 11, 2015. Britain has begun testing driverless cars in four cities, launching the first official trials ahead of a series of planned rule reviews to accommodate the new technology. (Photo by Suzanne Plunkett/Reuters)

21 year-old Chanel Tapper, with the amazing tongue and 35 year-old Aevin Dugas, with the beautiful hair was certified as world record breakers for the world’s longest tongue and the world’s biggest afro in the Guinness Book of World Records. (Photo by Guinness World Records)

A performer wearing costumes walk on stilts before a show during a lantern fair at the beginning of Chinese Lunar New Year, in Xi'an, Shaanxi province, February 11, 2016. (Photo by Reuters/Stringer)

People collect water from shallow wells dug along the Shabelle River bed, which is dry due to drought in Somalia's Shabelle region, March 19, 2016. The cabinet ministers of the federal republic of Somalia have held on Thursday their weekly meeting in Mogadishu and discussed on the drought situation in parts of the country and its humanitarian consequences. Chaired by the acting PM and justice minister Abdullah Ahmed Jama (Ilka-Jir), the cabinet noted with deep concern the the prevailing situation in Somalia, with one of the worst ever drought in two decades. (Photo by Feisal Omar/Reuters)

Everyone wants to get something for nothing - whether it's a lucky upgrade that means you can turn left when you get on a plane instead or heading off into the economy seats, or even getting a few extra features thrown in for free when you buy a new car.

As some of the sharpest businesses around, no-one understands this quite as well as casinos and that's why they all have a system that they call comps. It's short for "complimentary offers" and these are special treats specially designed to reward you for your loyalty to the casino in question. They're basically bonuses.

Women wearing traditional hats, known as a non la, sell fruits in Hoi An, Vietnam April 4, 2016. The non la hats are made of readily available materials such as palm leaves, tree bark and bamboo and are visible everywhere in the city, a UNESCO World Heritage site. Hoi An's history as a busy trading port is evident throughout its architecture, a mix of eras and styles, with traditional wooden Vietnamese houses, Chinese temples and French colonial buildings. (Photo by Jorge Silva/Reuters)