Christian pilgrims from Brazil embrace after they are baptized in the water of the Jordan River during a ceremony at the Yardenit baptismal site near the northern Israeli city of Tiberias October 15, 2014. (Photo by Finbarr O'Reilly/Reuters)

A member of the “Castellers Minyons de Terrassa” adjusts her belt before forming a human tower or ÒcastellÓ during the festival of the patron saint of Barcelona “The Virgin of Mercy” at Sant Jaume square in Barcelona, Spain, September 20, 2015. The formation of human towers is a tradition in Catalonia dating back to the 18th century. (Photo by Susana Vera/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.

Schoolchildren look at a lifelike animatronics display of a dinosaur at the dinosaur-themed Zoo-rassic Park in Singapore on November 16, 2016. To raise awareness on the sixth mass extinction, the Singapore Zoo and River Safari displayed lifelike dinosaur animatronics where visitors can trail along the Dinosaur Valley which does not involve living animals. (Photo by Roslan Rahman/AFP Photo)

CANADA: Stanley Ferdinand filets large trout he caught in Great Bear Lake in Deline, Northwest Territories, Canada September 8, 2016. (Photo by Pat Kane/Reuters)

South Sudanese traditional dancers prepare to welcome Pope Francis during his visit in Juba, South Sudan on February 3, 2023. (Photo by Thomas Mukoya/Reuters)

Lebanese actress Rita Hayek shows her 10km medal after participating in the 9th edition of the Women's Race in Beirut on March 19, 2023, under the slogan “Draw Your Path”. (Photo by Anwar Amro/AFP Photo)

A model presents a creation from the Gucci Fall-Winter 2022/2023 collection during Fashion Week in Milan, Italy, February 25, 2022. (Photo by Alessandro Garofalo/Reuters)