A cameraman films “Diana And Callisto” (circa 1556-59) oil painting by Venetian artist Titian as it goes on display for the first time at the National Gallery on March 1, 2012 in London, England.(Photo by Dan Kitwood/Getty Images)

A man passes by a wall with graffiti in Beirut, Lebanon, on May 29, 2019. (Photo by Bilal Jawich/Xinhua News Agency/Alamy Live News)

Actress Sophia Loren teases the hair of critic Gene Shalit in New York, Tuesday, February 20, 1979. During the filming of a segment for the NBC television “Today” show. In the background is a large photograph of Miss Loren. The segment is scheduled for airing later this week. (Photo by Dave Pickoff/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.

Car headlights illuminate a woman walking through city streets as snow accumulates on December 16, 2020 in Wilkes Barre, Pennsylvania. Winter Storm Gail is expected to bring more than a foot of snow in parts of the Northeast. (Photo by Mark Makela/Getty Images)

Collided passenger train cars are seen in Taebaek, South Korea, Tuesday, July 22, 2014. Two passenger trains collided head-on in eastern South Korea on Tuesday afternoon, killing one passenger and injuring dozens, fire officials said. (Photo by AFP Photo/Yonhap)

Tech. Sgt. Milo Hinson, 3rd Combat Camera Squadron, uses a flashlight while shooting a Berretta 9mm during the night-fire portion of Advance Weapons, Tactics and Techniques training in San Antonio. During night-fire training, airmen learn how to tactically illuminate targets with flashlights and practice using night vision goggles. (Photo by Staff Sgt. Jonathan Snyder/U.S. Air Force). 2011

Artist Sayna Soleimanpour performs a photoshoot in protest against the mistreatment and alienation of Turkish women based on their clothing, during a two-day curfew amid the spread of the coronavirus disease (COVID-19), on a deserted street in Istanbul, Turkey, early December 6, 2020. (Photo by Umit Bektas/Reuters)