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.

Hemispheric color differences on Saturn's moon Rhea are apparent in this false-color view from NASA's Cassini spacecraft in this March 2, 2010 file photo. (Photo by Reuters/NASA/JPL/SSI)

A smokejumper leaps from an airplane during a training flight above Winthrop, Washington, U.S., June 30, 2016. On a 100-degree day in early June, eight experienced firefighters did sit-ups in a semicircle training to parachute into a wildfire. Better known as “rookie candidates”, they were determined to make it through the five-week program at North Cascades Smokejumper Base in Winthrop, Washington, where the first experimental jumps occurred in 1939. (Photo by David Ryder/Reuters)

A thirsty timber wolf, Lithuania, 2018. (Photo by Erikas Plucas/Alamy Stock Photo)

A student uses a ruler to measure the distance between forks before a formal dinner at The International Butler Academy China on September 16, 2014 in Chengdu, China. Over the last several years, there has been a surge in demand among China's wealthy for Western-trained butlers, with many academies seeing large portions of their graduating classes hired by Chinese families or companies. (Photo by Taylor Weidman/Getty Images)

A cosplayer dressed as a “remote worker” with “corporate slave” written on his glasses poses for a photo on New Year's Eve at Comiket, the largest comic market that had been postponed for two years because of the coronavirus disease (COVID-19) pandemic, in Tokyo, Japan December 31, 2021. (Photo by Androniki Christodoulou/Reuters)

Natural world and wildlife shortlist. Lop Buri in Thailand is home to hundreds of macaques, which local residents consider to be disciples of the Hindu god Hanuman. While some people love them, others fear or even hate them. Despite the inconvenience they often cause, the macaques are generally respected and considered sacred. (Photo by Joan de la Malla/Sony World Photography Awards)