Sofia Evangelia Malkogeorgou and Evangelia Platanioti of Greece perform in the duet technical routine of the artistic swimming event during the Paris 2024 Olympic Games at the Aquatics Centre in Saint-Denis, north of Paris, on August 9, 2024. (Photo by Gonzalo Fuentes/Reuters)

(L-R) Sofía Vergara and Heidi Klum attend Netflix's Primetime Emmy afterparty at Hilex on September 15, 2024 in Los Angeles, California. (Photo by Roger Kisby/Getty Images for Netflix)

Archie, a Chinese Crested dog, sits with his tongue out before the start of the 20th Annual Ugliest Dog Competition at the Sonoma-Marin Fair June 20, 2008 in Petaluma, California. Owners of ugly dogs travel to Petaluma from all over the country to participate in the annual contest. (Photo by Justin Sullivan/Getty Images)

“It’s the end of the world, baby!” screams the title of the new 2012 calendar from Campari. Sensing the Mayan calendar’s apocalyptic spirit, Campari created a protagonist in supermodel Milla Jovovich to storm through the end of the world holding glasses and bottles of the red aperitif, all while dressed in impeccable couture. (Photo by Dimitri Daniloff/Campari)

This picture taken on January 25, 2015 shows a participant taking part in an ice water challenge in Zhangjiajie, central China's Hunan province. Participants were required to stay in an ice pond, holding an ice block while eating ice-cream with an electric fan blowing at them. (Photo by AFP Photo/Stringer)

Front end detail of the Hyundai Santa Cruz crossover concept truck as it is displayed during the first press preview day of the North American International Auto Show in Detroit, Michigan January 12, 2015. (Photo by Rebecca Cook/Reuters)

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.

(L-R) Jade Chapman, Maryam Maquillage, Mariah Carey, Laura Lee and Arika Sato attend M.A.C Cosmetics Mariah Carey Beauty Icon Launch at Baccarat Hotel on December 3, 2016 in New York City. (Photo by Theo Wargo/Getty Images for M.A.C)