Dancer of the Berlin State Ballet (Staatsballett Berlin) wear face masks as they perform during the dress rehearsal of Don Quixote in a production choreographed by Victor Ullate, amid the coronavirus disease (COVID-19) pandemic at Deutsche Oper opera house in Berlin, Germany, December 1, 2021. (Photo by Fabrizio Bensch/Reuters)

A contestant lies in a chili covered pool eating Chillies during a chili eating contest on July 8, 2018 in Ningxiang, Hunan Province of China. Citizen Tang Shuaihui ate 50 Chillies in one minute winning the contest. (Photo by VCG/Getty Images)

A soldier eats ice cream as she visits a zoo in Pyongyang, North Korea, September 12, 2018. (Photo by Danish Siddiqui/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 demonstrator holds a rose and shouts slogans in front of a riot policeman during an unauthorized march called by secondary students to protest against government education reforms in Valparaiso, Chile, May 26, 2016. (Photo by Rodrigo Garrido/Reuters)

A vendor sleeps as his son waits for customers at their roadside vegetable shop in New Delhi, February 12, 2019. (Photo by Adnan Abidi/Reuters)

A member of Extinction Rebellion Red Rebel Brigade protests against fracking gas outside Government Buildings in Dublin, Ireland on March 23, 2021. (Photo by Clodagh Kilcoyne/Reuters)

In this September 14, 2017 photo, young women pose for a photo inside their squatter building that used to house the Brazilian Institute of Geography and Statistics (IBGE) in the Mangueira slum of Rio de Janeiro, Brazil. Many lower-middle class Brazilians who gained ground during the boom years have since slid back closer to the poverty line. (Photo by Felipe Dana/AP Photo)