An Indian women offers early-morning prayers or a “puja” at a ghat early in the morning on the banks of the Betawa River in Orchha in the state of Madhya Pradesh on July 5, 2015. (Photo by Rebecca Conway/AFP Photo)

Salcomp players huddle at the center of the pitch of Arena da Amazonia after winning the Peladao amateur soccer tournament in Manaus, Brazil, Saturday, February 16, 2019. It is the team's second title, the first was in 2011. (Photo by Victor R. Caivano/AP Photo)

A protester is taken away by policewomen after storming into the government headquarters in Hong Kong September 27, 2014. (Photo by Bobby Yip/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.

Fire photographer Tod Sudmeier gets hit with flying embers from strong winds at the Solimar brush fire that started early Saturday morning in Ventura County, California December 26, 2015. (Photo by Gene Blevins/Reuters)

Participants struggle to reach the prizes during a greased-pole climbing competition held as a part of the independence day celebrations in Jakarta, Indonesia, Sunday, August 17, 2014. Indonesia is celebrating its 69th independence from the Dutch colonial rule. (Photo by Dita Alangkara/AP Photo)

A baby rhesus macaque (Macaca mulatta) looks up as it plays with a tiger cub at a zoo in Hefei, Anhui province, August 2, 2012. (Photo by Jianan Yu/Reuters)

A Bedouin rifleman hides behind his camel while he carefully takes aim in the Sahara desert. (Photo by Three Lions/Getty Images). Circa 1955