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.

Miss Earth 2016 candidates wearing environmental statement sashes lineup during a press presentation in Manila, Philippines, 11 October 2016. Eighty three young women from around the globe converged in Manila for the international beauty event. Miss Earth is a pioneering beauty pageant that serves as a vehicle for environmental advocacy. (Photo by Mark R. Cristino/EPA)

“Suri tribes boys are collecting the blood of a cow in a calabash the vein of the animal was opened with a bow and an arrow. Like most pastoralists the Surma people are drinking fresh blood which is from the cow vein. Only some minutes after the wound at the vein is closed again the animals are back with their herd”. (Photo and caption by Anthony Pappone)

“Very small forest-dwelling wallabies are known as pademelons (genus Thylogale) and dorcopsises (genera Dorcopsis and Dorcopsulus). The name wallaby comes from the Eora Aboriginal tribe who were the original inhabitants of the Sydney area. Wallabies are herbivores whose diet consists of a wide range of grasses, vegetables, leaves, and other types of foliage”. – Wikipedia

Photo: A baby wallaby sits in a zoo attendant's lap at Edogawa Natural Zoo on August 4, 2009 in Tokyo, Japan. The staff of the zoo have raised the young wallaby after her mother neglected her. (Photo by Junko Kimura/Getty Images)

New Market traders rescue an injured shopkeeper who got hurt during a clash with students from Dhaka college in Dhaka on April 19, 2022. (Photo by Munir Uz Zaman/AFP Photo)

Oleh Psiuk, frontman of Ukraine's Kalush Orchestra and vocalist Sasha Tab, right, are pictured by a fan before leaving the Universo Hotel, after winning the Grand Final of the Eurovision Song Contest, in Turin, Italy, Sunday, May 15, 2022. (Photo by Luca Bruno/AP Photo)

Jeret Cooper of Vernon, British Columbia rides the horse Einstein Quest in the novice bareback event during the Calgary Stampede rodeo in Calgary, Alberta, Canada on July 11, 2022. (Photo by Todd Korol/Reuters)

A goat hops from student to student during a goat yoga class at the University of Tennessee on August 25, 2022 as part of welcome back week. The session was organised by Goat Yoga Nashville. (Photo by Matt Hamilton/Chattanooga Times Free Press via AP Photo)