People dance during a heavy metal concert at Omni Space in Beijing, China, August 14, 2020. China boasts a small but buoyant heavy metal scene, where bands mix genre standards with Chinese elements. Black metal is a sub-genre that creates a dark, moody atmosphere layering heavily distorted guitars and high-pitched vocals. (Photo by Thomas Peter/Reuters)

A model walks during the Black Tape Project fashion show at New York Fashion Week Fall 2024 powered by Art Hearts Fashion at The Angel Orensanz Foundation on February 11, 2024 in New York City. (Photo by Arun Nevader/Getty Images for Art Hearts Fashion)

A driver pulls a handgun on protesters after they broke his trucks lights on March 28, 2021 in Salem, Oregon. The protesters clashed with occupants of vehicles that had participated in an American flag-waving car caravan, despite law enforcements efforts to to keep the groups separate. (Photo by Nathan Howard/Getty Images)

Bella Hadid arriving at her hotel on December 7, 2017 in London, England. (Photo by Palace Lee/PacificCoastNews)

Medic James E. Callahan of Pittsfield, Mass., gives mouth-to-mouth resuscitation to a dying soldier in war zone D, about 50 miles northeast of Saigon, June 17, 1967. Thirty-one men of the 1st Infantry Division were reported killed in the guerrilla ambush, with more than 100 wounded. (Photo by Henri Huet/AP Photo)

Rick Sorenson, owner of the Rio Ramaza Marina, wades in the Sacramento River after securing an old paddlewheel boat on his property as the river makes its way up the levee on Garden Highway in Sacramento, Calif., Monday, January 9, 2017. (Photo by Hector Amezcua/The Sacramento Bee via AP Photo)

Suzanna Shahbazian of Canada competes in the Individual Exercises Final during Pan American Gymnastics Championships Rio de Janeiro 2022 at Carioca Arena 1 on July 09, 2022 in Rio de Janeiro, Brazil. (Photo by Buda Mendes/Getty Images)

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.