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 boy looks for sellable materials close to the burning garbage in the permanent waste land under Sylhet City Corporation for a living, on January 15, 2015. (Photo by Md. Akhlas Uddin/Pacific Press)

Costumed guests arrive for the “Life Ball” charity event at the Rathaus city hall in Vienna, Austria, 10 June 2017. The 24th Life Ball is a charity fundraiser for HIV and Aids projects. (Photo by Christian Bruna/EPA/EFE)

Yippie leader Jerry Rubin, barred on December 4, from House Un-American Activities subcommittee hearing, aims a toy gun in “self defense” outside the Washington hearing room on December 5, 1969. Rubin showed up in his Santa Clause suit because he believed it was typical of the committee which, he said, “is a total circus”. (Photo by Bob Daugherty/AP Photo)

Jo Swinson, Leader of the Liberal Democrats takes part in some boxing practice as she campaigns at a boxing gym for young people on November 13, 2019 in London, England. The United Kingdom will hold a general election on December 12. (Photo by Leon Neal/Getty Images)

A woman walks past a mural depicting RM, a member of K-pop group BTS, in Goyang, northwest of Seoul, on June 15, 2022. (Photo by Anthony Wallace/AFP Photo)

Members of Afghan ninja team “Kabura Vahdet” practices Asian martial arts in Tehran, Iran on June 17, 2022. (Photo by Fatemeh Bahrami/Anadolu Agency via Getty Images)

Women take selfies as they wait for the subway at Penn Station, New York, December 26, 2023. (Photo by Charly Triballeau/AFP Photo)