A reveler playfully sticks out her tongue during a street pre-carnival party by the “Cordao do Boitata” Block, in Rio de Janeiro, Brazil, Sunday, February 12, 2023. Revelers are taking to the streets for the open-air block parties, leading up to Carnival's official Feb. 17th opening. (Photo by Bruna Prado/AP Photo)

A hand reaches out to touch a dinosaur during the “Jurassic Quest” experience at Broward County Convention Center on July 08, 2022 in Fort Lauderdale, Florida. (Photo by Joe Raedle/Getty Images)

Adrian Reyes, representing Canada, prepares backstage before competing in the Miss International Queen pageant on June 24, 2023 in Pattaya, Thailand. Thailand hosts Miss International Queen, the largest and most prestigious international transgender beauty pageant. The pageant, held annually in Pattaya, Thailand is held takes place during Pride month. Throughout Thailand, Thai LGBTQ activists have held Pride events calling for equality and pressuring the incoming government to move forward with legislation that would allow marriage for all. (Photo by Lauren DeCicca/Getty Images)

Youth council member Mia Buckles plays with 18-month-old Kobe Buckles-Benson as Canada's Prime Minister Justin Trudeau visits the Cowessess First Nation, where a search had found 751 unmarked graves from the former Marieval Indian Residential School near Grayson, Saskatchewan, Canada on July 6, 2021. (Photo by Shannon VanRaes/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.

Alex Lual (R) in action against Trent Girdham (L) during the undercard bouts ahead of the WBO Asia Pacific Super Welterweight Title Bout between Tim Tszyu and Takeshi Inoue at Qudos Bank Arena, in Sydney, New South Wales, Australia, 17 November 2021. (Photo by Dan Himbrechts/EPA/EFE)

A person throws a flower towards Britain's Queen Elizabeth's coffin, as it is transported, on the day of her state funeral and burial, in London, Britain on September 19, 2022. (Photo by Carlos Barria/Reuters)

A festivalgoer enjoys the weather in the circus area at the Glastonbury Festival at Worthy Farm in Somerset, United Kingdom on Thursday, June 22, 2023. (Photo by Ben Birchall/PA Images via Getty Images)