A demonstrator with a Palestinian flag painted on her face takes part in a march to express solidarity with Palestinians in Gaza, in Beirut, Lebanon on October 13, 2023. (Photo by Mohamed Azakir/Reuters)

A canine chase a target during a racing competition on the outskirts of Charsadda on January 14, 2024. (Photo by Abdul Majeed/AFP Photo)

Debbie Barton from Blufton, South Carolina, asks supporters of Republican presidential candidate and former U.S. President Donald Trump to sign a petition calling for one day of voting and the eradication of voting machines, ahead of a “Team Trump” event in Beaufort, South Carolina, U.S. February 21, 2024. (Photo by Evelyn Hockstein/Reuters)

Boat party in Malta on July 17, 2023. Malta is the new party destination. Parties, sеx and bad behaviour mixed with cheap prices and wonderful weather have made malta the place to be. (Photo by Thea Jacobs/The Sun)

During a jungle survival program February 20, 2013 taught by Royal Thai Special Forces in Sannapit, Thailand, U.S. Marines learned to catch cobras and drink their fresh blood, not to mention eat forest insects and pull the heads off of chicken. The training was part of Operation Cobra Gold 13, the 32nd edition of international military exercises hosted by the Thai. According to a U.S. Marines press release, Cobra Gold is the largest exercise of its kind in Asia and incorporates troops from five other nations in addition to the U.S. and Thailand. The Daily Mail reports that the Marines were invited to experience the local custom of drinking cobra blood after being taught to catch and kill cobras in the wild. As CNN notes, Cobra blood is believed to be a panacea and aphrodiasic in parts of Southeast Asia. In Jakarta, vendors can earn over $100 a night selling shots of cobra blood mixed with liquor. (Photo by Pornchai Kittiwongsakul/AFP Photo)

Women perform a pole dancing routine during the national day celebration of “Urban Pole” dance along a street in Monterrey, Mexico, on June 9, 2013. (Photo by Daniel Becerril/Reuters)

Mongolian herder, Khurelsukh, throws the carcass of a goat onto a heap as he struggles to deal with losing a quarter of his herd, on March 8, 2010 in Bayantsogt, Tuv province, Mongolia. (Photo by Paula Bronstein /Getty Images)

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.