Members of China Disabled Peoples Performing Art Troupe perform “Thousand-arm Goddess of Mercy” during a show on March 12, 2005 in Guangzhou of Guangdong Province, China. China Disabled Peoples Performing Art Troupe was established in 1987. It is an amateur mass art troupe composed of visually impaired, audibly impaired and physically and mentally challenged people. In the past nearly two decades, the troupe has visited more than 30 countries and regions, winning the hearts of audiences all over the world by their solid background of Chinese Culture and their colourful national charm. (Photo by China Photos/Getty Images)

A tattoo artist applying ink on a girl' s arm during the 2017 Moscow Tattoo Festival at Moscow' s Amber Plaza Shopping Center in Moscow, Russia on April 1, 2017. Tattoo artists from all over the world take part in the event. The festival' s program includes a tattoo contest, body taping art marathon, masterclasses, round table discussions and conferences. (Photo by Valery Sharifulin/TASS)

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.

Mikhail Baburin, 66, talks to his cat Marquis at his house in the remote Siberian village of Mikhailovka, Krasnoyarsk region, Russia, December 5, 2016. Baburin, a former Navy man, barge worker and employee of a military plant in Krasnoyarsk, is the last inhabitant of Mikhailovka, which was founded in the 19th century by migrants from Russia's Mordovia region. He moved in 2000 to Mikhailovka where he was born and has lived there all alone for the last 10 years with only domestic animals. (Photo by Ilya Naymushin/Reuters)

Life as tenant farmers in Kasungu, northern Malawi, can be a struggle for families trapped in poverty, who feel forced to rely on their children’s help, impacting schooling. Here: A tobacco field at a farm in Kasungu region, Malawi. Tobacco is the country’s most important export crop, with tobacco leaf from Malawi filling cigarettes found all over the world. Here: Tiyamike Phiri hopes to become a nurse because she wants to travel the country and help others. (Photo by David Levene/The Guardian)

Fans in Star Wars costumes attend the world premiere of Disney's “Star Wars: Rise of Skywalker” at the TCL Chinese Theatre in Hollywood, California on December 16, 2019. (Photo by Valerie Macon/AFP Photo)

Zoo keeper Ross Poulter holds a White's Tree Frog in Edinburgh Zoo's new tropical forest zone on September 9, 2011 in Edinburgh, Scotland. The Brilliant Birds Exhibit which brings together beautiful and rare birds from all over the world is now more colourful and unusual, with the unveiling of the zoo's new tropical forest zone bringing together a collection of vertebrates, invertebrates and amphibians for the very first time. (Photo by Jeff J Mitchell/Getty Images)