Demonstrators who blocked a main road with their vehicle to demand fuel near President Gotabaya Rajapaksa's residence, argue with a police officer, during the country's economic crisis, in Colombo, Sri Lanka on June 29, 2022. (Photo by Dinuka Liyanawatte/Reuters)

In this picture taken with a drone a man and a woman enjoy the beautiful weather at the Langwieder See (Lake Langwieder) in Munich, Germany, Thursday, June 18, 2020. (Photo by Sven Hoppe/dpa via AP Photo)

An injured protestor grieves in pain as police fire tear gas to disperse protesting members of the Inter University Students Federation during an anti government protest in Colombo, Sri Lanka, Thursday, May 19, 2022. Sri Lankans have been protesting for more than a month demanding the resignation of President Gotabaya Rajapaksa, holding him responsible for the country's worst economic crisis in recent memory. (Photo by Eranga Jayawardena/AP 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.

A market trader in Gaibandha in Bangladesh on September 25, 2019, surrounded by bottle gourd vegetables, which sell for around 3p ($ 0.04) each. (Photo by Solent News)

An alligator named Muja is seen in its enclosure in Belgrade's Zoo, Serbia, August 14, 2018. Muja is officially the oldest American alligator in the world living in captivity. He was brought to Belgrade from Germany in 1937, a year after the opening of the Zoo. Muja survived three bombings of Belgrade, the Second World War and all hardships the Zoo went through. (Photo by Marko Djurica/Reuters)

A vender arranges goods for sale at a market on the outskirts of Buenos Aires, Argentina, Wednesday, January 10, 2024. (Photo by Natacha Pisarenko/AP Photo)

A snow leopard looks on from an inside of a cage, after being captured from the southern plains of Nepal and brought to the central zoo, which wildlife experts say is rare for the animal that is found in the higher altitude, in Kathmandu, Nepal on January 26, 2024. (Photo by Navesh Chitrakar/Reuters)