A camel foams at the mouth as he is whipped by a robot jockey during a race at Nad al-Sheba on December 6, 2006 in Dubai, United Arab Emirates. This is the first season that robotic jockeys have been used to race camels in Dubai. Controversially children from India were used to ride the camels in past seasons. These robot jockeys costing 15000GBP and up, were designed in Geneva and include shock absorbers and GPS tracking systems. The camel's owners control them from their speeding four wheel drives at the side of the track. (Photo by Chris Jackson/Getty Images)

Aimee, 19, who has Down syndrome, has make-up applied by her mother before a presentation in Monterrey, Mexico, in this picture taken April 9, 2016. The association “Abrazame con Discapacidad” (“Embrace me with Disabilities”) teaches folk dance to low-income people with Down syndrome and manages presentations at public events where they receive a payment, as part of a therapy that helps improve their motor system, learning and self-esteem, the association said. (Photo by Daniel Becerril/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.

A massive positive cloud-to-ground lightning strike hits in Coolidge, Arizona, 31 August 2016. Thousands of rain drops merge to form mammoth travelling sheets of water in these breathtaking monsoons. Veteran storm chaser and photographer Mike Olbinski captured the stunning beauty of monsoons in timelapses and stills while chasing storm systems across America. (Photo by Mike Olbinski/Barcroft Images)

A kid from Sichuan provice smokes at an assistance center February 23, 2005 in Shenzhen, Guangdong Province, China. The kids, ranging in age from 7 to 16, are temporary residents of the center, one of the institutions established by China's departments of civil affairs to help and administer beggars, vagrants and juvenile delinquents, after rescission of China's compulsory detainment and relocation system. (Photo by Cancan Chu/Getty Images)

A girl looks out from the window of a “La Sabana” tourist train in La Caro March 1, 2015. The “La Sabana” tourist train that runs through the capital was founded by Eduardo Rodriguez, a railway engineer. Rodriguez has worked on Colombia's railway system his whole life and now, with an air of nostalgia, transports thousands of tourists in renovated steam locomotives that he fixes in Bogota's Central Station which dates back to 1913. (Photo by Jose Miguel Gomez/Reuters)

A member of the “Exit Point” amateur rope-jumping group jumps from a 44-metre high (144-feet high) waterpipe bridge in the Siberian Taiga area outside Krasnoyarsk, September 28, 2014. Fans of rope-jumping, a kind of extreme sport involving a jump from a high point using an advanced system of amortization including mountaineering and rope safety equipment, attended the Golden Autumn group's jumping season. (Photo by Ilya Naymushin/Reuters)

A sculptural artwork depicting former Chilean dictator Augusto Pinochet and headless presidents shot by a hooded high school student (not pictured) is seen at the Contemporary Art Museum in Santiago, December 2, 2014. The artwork, part of the “El ladrillo angular” (The angular brick) exhibition, portrays a student fighting against the ongoing continuity of dictatorship because of a political and economic system which has been impossible to destroy, according to “Papas Fritas” the artwork's creator. (Photo by Ivan Alvarado/Reuters)