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 fisherman with a close bond to cormorants uses the flock of birds to catch big fish in Li river in Guilin, China. The aquatic birds can be seen perching on a bamboo raft before swooping into the calm water to grasp hold of prey. (Photo by Julia Wimmerlin/Solnet News & Photo Agency)

A woman wearing a face mask to help protect against the spread of the new coronavirus crosses a stream in Seoul, South Korea, Wednesday, July 15, 2020. (Photo by Lee Jin-man/AP Photo)

A food market shows off rows upon rows of dead animals, some of which have been beaten to death. Dogs and chickens can be seen lined up with their mouths hanging wide open. Shoppers even pick up some of the dogs and bats as they look for the best on the market. Retired biologist and amateur photographer Alf Jacob Nilsen took the shocking pictures of the market during a visit to Tomohon Village in Northern Sulawei, Indonesia. Pictured: Flying foxes (bats) for sale at the market. (Photo by Alf Jacob Nilsen/Solent News)

Iranians wearing face masks against the Covid-19 coronavirus attends Laylat al-Qadr prayers, one of the holiest nights during the Muslim fasting month of Ramadan, outside a mosque in the Tehran, on May 13, 2020. (Photo by Atta Kenare/AFP Photo)

A production department of a textile factory is seen abandoned in Kaduna, Nigeria November 3, 2016. President Muhammadu Buhari hopes to revive the once flourishing textile and leather industries in northern Nigeria to end the country's dependence on oil exports and diversify Africa's biggest economy. (Photo by Afolabi Sotunde/Reuters)

Police officers arrest a protester during an anti-lockdown march in Liverpool, United Kingdom on November 21, 2020. The StandUpX movement organised a protest under the banner March for Freedom, Save Our City. (Photo by Mercury Press)

Tourists play on the “Big” piano inside of the toy store FAO Schwarz on the last day that the store will be open in New York, July 15, 2015. FAO Schwarz will officially close the doors of its flagship Fifth Avenue toy store in New York City on Wednesday night, to the dismay of shoppers charmed by the iconic destination for childhood fun. (Photo by Lucas Jackson/Reuters)