Sandra Brown, 40, rides the Skyslide on the 69th and 70th floors of the U.S. Bank Tower which is attached to the OUE Skyspace LA observation deck in downtown Los Angeles, California, U.S. June 20, 2016. (Photo by Lucy Nicholson/Reuters)

This photo take on December 16, 2016 shows macaques monkeys playing on a motorbike in the grounds of a temple in Jaipur in the Indian state of Rajasthan. (Photo by Dominique Faget/AFP Photo)

A woman steers her stand-up paddle board using an umbrella as a sail at Ladoga lake near the city of Olonets, 300 kilometers (186 miles) north-east of St. Petersburg, Russia, Friday, July 22, 2022. (Photo by Dmitri Lovetsky/AP Photo)

Switzerland's forward #19 Eseosa Aigbogun (L) fights for the ball with Philippines' defender #16 Sofia Harrison (R) and Philippines' forward #21 Katrina Guillou during the Australia and New Zealand 2023 Women's World Cup Group A football match between the Philippines and Switzerland at Dunedin Stadium in Dunedin on July 21, 2023. (Photo by Sanka Vidanagama/AFP 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.

Jamaica's Tissanna Hickling competes in the women's long jump qualification during the World Athletics Championships at the National Athletics Centre in Budapest on August 19, 2023. (Photo by Kirill Kudryavtsev/AFP Photo)

A climate activist wears an oxygen mask to demonstrate the possibility of pumping oxygen from a tree in a bottle in the future, during a protest against the government's deforestation practices of Sri Lanka's main wildlife forests for developments in Colombo, Sri Lanka on March 22, 2021. (Photo by Dinuka Liyanawatte/Reuters)

A woman holds a cutout of President Donald Trump's face at a rally in Washington in support of Trump called the “Save America Rally” on January 6, 2021. (Photo by Jacquelyn Martin/AP Photo)