Japan's Naomi Osaka sits with her towel over her head during a break in her third round loss to Coco Gauff of the U.S. at the Australian Open tennis championship in Melbourne, Australia, Friday, January 24, 2020. (Photo by Lee Jin-man/AP Photo)

Vlada Nikolchenko of Ukraine performs with the ribbon during the 36th European Rhythmic Gymnastics Championships in Kyiv, Ukraine, Sunday, November 29, 2020. Athletes from 23 countries participate in the championship in Kyiv. (Photo by Efrem Lukatsky/AP Photo)

Models wait backstage ahead of the Carolina Herrera Fall/Winter 2023 collection show during the New York Fashion Week in New York City, U.S., February 13, 2023. (Photo by Andrew Kelly/Reuters)

British singer-songwriter Rita Ora has her knickers in a twist as she gets animated backstage at a music festival in Lithuania in the last decade of July 2024. (Photo by Splash News and Pictures)

The USA’s Beatriz Hatz competes at Women's Long Jump -T64 final at the Stade de France stadium, during the 2024 Paralympics, Saturday, August 31, 2024, in Paris, France. (Photo by Ümit Bektaş/Reuters)

Ecuador's Ronald Zabala G., riding, Forever Young Wundermaske, fall off their horse during the Equestrian Cross Country competition at Chateau de Versailles for the 2024 Summer Olympics, Sunday, July 28, 2024, in Versailles, France. (Photo by Mosa'ab Elshamy/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 handout photo made available by Limex Images of Pete McLeod of Canada (R) and Kirby Chambliss of the United States flying over the city of Kazan prior to the fifth stage of the Red Bull Air Race World Championship in Russia on August 22, 2018. (Photo by Joerg Mitter/EPA/EFE/Limex Images)