Greece's Maria Sakkari reacts during her women's singles quarter-final tennis match against Poland's Iga Swiatekon Day 11 of The Roland Garros 2021 French Open tennis tournament in Paris on June 9, 2021. (Photo by Gonzalo Fuentes/Reuters)

Revelers stained with colored powder cheer during the Holi festival celebrations in Chennai, India, 08 March 2023. Holi, also known as the “Festival Of Colors” is an ancient Indian Hindu festival symbolizing the victory of good over evil and marking the arrival of spring. It is celebrated with joyful gatherings during which revelers cover each other in colored powders. (Photo by Idrees Mohammed/EPA/EFE)

Two carnival revellers masquerade as Leonardo da Vinci's painting “Mona Lisa” pose in St. Mark's Square in Venice, Italy, Sunday, January 31, 2016. Carnival-goers in Venice are being asked by police to momentarily lift their masks as part of new anti-terrorism measures for the annual festivities. (Photo by Domenico Stinellis/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.

A girl smiles as her hair is blown by a strong wind in the Chinatown area in Yokohama, near Tokyo, Friday, January 27, 2017. (Photo by Koji Sasahara/AP Photo)

Evel Knievel is shown in his rocket before his failed attempt at a highly promoted 3/4-mile leap across Snake River Canyon in Twin Falls, Idaho, on September 8, 1974. The jump failed when the parachute on his rocket malfunctioned, opening prematurely. Knievel was uninjured. (Photo by AP Photo)

A pelican on a lake in California in the first decade of January 2024 deftly snares a large trout after scooping it up, tossing it into the air and catching it in its bill. (Photo by Jiahong Zeng/Solent news)

British sculptor Laurence Edwards' striking bronze figures, Walking Men, at Blenheim Palace in Oxfordshire, UK on April 9, 2024. The 8ft tall figures are seen to be anti-heroic and seem to have come from the earth itself. Branches, leaves and clods of clay are woven through them, making it unclear where human and ground begin and end. (Photo by Pete Seaward/South West News Service)