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)

British actress Millie Bobby Brown and Danish actor Mads Mikkelsen break the sake barrel during the opening ceremony for Osaka Comic Con 2023 at the Intex Osaka on May 5, 2023 in Osaka, Japan. (Photo by Jun Sato/WireImage)

British singer and songwriter Charlotte Emma Aitchison aka Charli XCX poses in the green room for a portrait before the Sonos And Pandora Present “An Evening With Charli XCX” event at Sonos Studio on June 10, 2014 in Los Angeles, California. (Photo by Joe Scarnici/Getty Images for Sonos)

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.

Carlos Melendez prepares to feed his pet squirrel “Colita” in downtown San Salvador January 29, 2015. (Photo by Jose Cabezas/Reuters)

Participants climb over a wall at the “Tough Mudder” endurance event series in Arnsberg September 6, 2014. Competitors who took part in the endurance event saw themselves having to overcome various military style obstacles. (Photo by Ina Fassbender/Reuters)

Tanzania, 1964. A touching moment between primatologist and National Geographic grantee Jane Goodall and young chimpanzee Flint at Tanzania's Gombe Stream Reserve. (Photo by Hugo van Lawick via National Geographic)

People carrying red umbrellas march through downtown Skopje, Macedonia, marking the International Day to End Violence against s*x Workers, Thursday, December 17, 2015. A group of s*x workers, supported by members of non-government organizations, rallied Thursday demanding rights for the s*x workers and destigmatization of their profession. The banner reads: The Stigma Kills. (Photo by Boris Grdanoski/AP Photo)