A man wearing a beard imprinted facemask as a preventive measure against the COVID-19 coronavirus walks along a street in New Delhi on June 19, 2020. India has recorded more than 380,000 cases of COVID-19, the fourth-highest in the world, with over 12,500 deaths, health ministry data show. (Photo by Jewel Samad/AFP Photo)

Two women look at the Cumbre Vieja volcanic eruption from the distance in Los Llanos de Ariadne in La Palma, Canary Islands, Spain, late 05 October 2021 (issued 06 October 2021). The main cone of the La Palma volcano suffered a partial collapse of its structure 03 October, while effusive activity has increased after 15 days of its beginning. According to experts the volcano is far from ending its volcanic activity. (Photo by Miguel Calero/EPA/EFE)

Police fire rubber bullets as they help an Atletico Paranaense fan during clashes between Vasco da Gama soccer fans and Atletico Paranaense fans at their Brazilian championship match in Joinville in Santa Catarina, on December 8, 2013. Dozens of fans fought a savage battle on the terraces at the match on Sunday, interrupting play for more than one hour and leaving at least three people reportedly in serious condition. (Photo by Carlos Moraes/Agência O DIA)

In this June 6, 1966 file photo, civil rights activist James Meredith pulls himself across Highway 51 after being shot in Hernando, Miss. Meredith, who defied segregation to enroll at the University of Mississippi in 1962, completed the march from Memphis, Tenn., to Jackson, Miss., after being treated for his wounds. (Photo by Jack Thornell/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.

Tree trunks and rocks are set up to support a leaning wall of Li Yonghua's damaged cave house in an area where land is sinking next to a coal mine, in Helin village of Xiaoyi, China's Shanxi province, August 2, 2016. (Photo by Jason Lee/Reuters)

MAKS – 2011 provides experts and businessmen a rare opportunity to establish contacts at various levels, further development of R&D and production cooperation and search for new business partners.

Young children at a Bristol, Great Britain health centre unsure of the benefits of sun-lamps and the special glasses that must be worn, July 1948. The health centre was part of the newly introduced free National Health Service. (Photo by Popperfoto/Getty Images)