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.

Public Space series, 2015. This series by Morteza Niknahad and Behnam Zakeri tends toward cinema, taking an almost cartoonish view of modern life in Iran. This work was inspired by the social life of dolphins. (Photo by Morteza Niknahad and Behnam Zakeri/The Guardian)

Dawn at Blyth beach huts in Northumberland, with the prospect of warm weather over the coming weekend on Friday, October 8, 2021. (Photo by Owen Humphreys/PA Images via Getty Images)

A woman plays on a swing on the beach in Santa Monica, Calif., Wednesday, June 22, 2022. (Photo by Jae C. Hong/AP Photo)

The Balance Bike Quad Eliminator being run (and organised) by GT Bicycles at the Malverns Classic, Start Line, Eastnor Deer Park, Eastnor, in Herefordshire on Friday 26th August 2022. Youngsters enjoy the thrills & spills of balance bike riding as they partake in the annual event held in rural Herefordshire. The thrills and spills as rider No. 013, Kelia Ranes tries hard to avoid a fallen competitor. (Photo by Richard Stanton/The Times)

A woman along with a child walk past a wall mural in Mumbai on November 29, 2022. (Photo by Punit Paranjpe/AFP Photo)

A pedestrian carries a shopping bag and looks at his phone while walking past a mural decorating a construction site in central Sydney on November 6, 2023. (Photo by David Gray/AFP Photo)

Lightning streaks across the skies over the coastal port city of Batroun, some 43km north of the Lebanese capital Beirut on December 6, 2023. (Photo by Ibrahim Chalhoub/AFP Photo)