People are seen at Avalon Beach on December 18, 2020 in Sydney, Australia. A cluster of Covid-19 cases on the northern beaches of Sydney has grown to 28, prompting NSW health officials to urge residents of affected suburbs to stay home. Traffic at Sydney Airport has increased as people rush to leave the city with several states imposing quarantine restrictions for New South Wales residents. (Photo by Jenny Evans/Getty Images)

A man presents a self-made robot that local media reported is able to carry a person, in Heihe, Heilongjiang province, China, April 5, 2017. (Photo by Reuters/China Daily)

Mariam Emad from Parkour Egypt “PKE” practices her parkour skills around buildings on the outskirts of Cairo, Egypt on July 20, 2018. A group of Egyptian women gather at an abandoned park in a Cairo suburb once a week, climbing walls and jumping around in the strenuous physical discipline known as Parkour, while also challenging the country's conservative social norms. (Photo by Amr Abdallah Dalsh/Reuters)

A reveller performs while attending the block party “Galo da Madrugada” during carnival festivities in Sao Paulo, Brazil on February 25, 2020. (Photo by Rahel Patrasso/Reuters)

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.

“Grit and Glamour”, a retrospective of the late British photographer Elsbeth Juda, who fled Nazi occupation and came to England in 1933, is at the Jewish Museum, in London, until July 1, 2018. Here: Shelagh Wilson, Copacabana beach, Rio de Janeiro, 1951. (Photo by Elsbeth Juda Archive/Victoria and Albert Museum)

Runner-up; Hon Yen marine ecosystem. Phu Yen, Vietnam. Every year between May and August, the coral of this rich and diverse ecosystem becomes exposed at low tide. (Photo by Truong Hoai Vu/Royal Society of Biology Photography Competition)

A small flock of birds seems to be giving an escort to an airliner on final approach to Reagan Washington National Airport in Arlington, Virginia on January 12, 2022. The scene took place over Gravelly Point which is an area within the National Park Service's George Washington Memorial Parkway. (Photo by Michael S. Williamson/The Washington Post)