Anja Rubik poses as she arrives for the screening of the film “Dolor Y Gloria (Pain and Glory)” at the 72nd edition of the Cannes Film Festival in Cannes, southern France, on May 17, 2019. (Photo by Stephane Mahe/Reuters)

Model Bella Hadid poses for photographers at the photo call for the film “Pain and Glory” at the 72nd international film festival, Cannes, southern France, Friday, May 17, 2019. (Photo by Arthur Mola/Invision/AP Photo)

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.

The camera rolls as actors dressed as historical Chinese soldiers act as though they have been hit by artillery, during filming of “The Last Prince” television series on location near Hengdian World Studios near Hengdian July 24, 2015. Hundreds of well-trained actors and other professionals are available at the Hengdian World Studios. The well-organised team coordinate complicated battle scenes to satisfy the huge appetite for productions about the war against Japan. (Photo by Damir Sagolj/Reuters)

Michael Read, director of Flight Operations from New Zealand-based Martin Aircraft Company, flies a Martin Jetpack during a demonstration at a water park in Shenzhen, China December 6, 2015. KuangChi Science Ltd, a Hong Kong-listed Chinese company and investor of Martin Aircraft, will sell the flying machine in mainland China for 1.6 million yuan ($249,902), according to the company. (Photo by Bobby Yip/Reuters)

This teenager from Anhui Province has Marfan syndrome, which has caused his neck to become very long. His father says that he has three extra vertebrae, according to Anhui News.

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)

This photo taken on February 1, 2018 shows a worker trimming the skin imperfections of a silicone doll at a factory of EXDOLL, a firm based in the northeastern Chinese port city of Dalian. With China facing a massive gender gap and a greying population, a company wants to hook up lonely men and retirees with a new kind of companion: “Smart” sеx dolls that can talk, play music and turn on dishwashers. (Photo by Fred Dufour/AFP Photo)