Two pins featuring former North Korean leader Kim Il Sung wearing different facial expressions are displayed in a glass case of Thomas Hui at his apartment in Hong Kong, China April 11, 2016. Collector Thomas Hui, 37, a former bank employee in Hong Kong, who is fascinated by North Korean pins and badges, has gathered over 100 featuring former leaders Kim Il Sung and Kim Jong Il, and has been buying and trading these Communist accessories since 2008. (Photo by Bobby Yip/Reuters)

Italian illusionist Arturo Brachetti perfoms in the mirrored mazes of Camera Obscura on August 06, 2024 in Edinburgh, Scotland. His show SOLO which is running at Pleasance’s EICC sees over fifty characters come to life through illusions, transformations and some magic tricks. (Photo by Jeff J. Mitchell/Getty Images)

The Royal Castle is seen a veil of heavy winter smog in Budapest, Hungary on January 30, 2017. (Photo by Laszlo Balogh/Reuters)

The moon rising above the Forth Rail Bridge in The Firth of Forth from North Queensferry, England on July 16, 2019. (Photo by South West News Service)

One of the busiest areas in Birmingham, United Kingdom last night was Ludgate Hill in the city's Jewellery Quarter. Brits enjoying the hottest August day for almost 20 years spilled out of packed pubs on August 7, 2020 after sunbathing on beaches around the country as the mercury rose to 36.4C. (Photo by SnapperSK/The Sun)

Photo taken at the top of the Canton Tower, a landmark in Guangzhou, on August 7, 2022 shows the Pearl River running through downtown of Guangzhou, capital of south China's Guangdong Province. (Photo by Liu Dawei/Xinhua News Agency)

The sun rises behind The Royal Liver Building in Liverpool, Merseyside on Tuesday, January 17, 2023. (Photo by Peter Byrne/PA Images via 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.