This strange coral-looking specimen is actually a mushroom. The photo, “Beautiful Destroyer”, was taken in the Panamanian tropical rainforest where the mushroom produces nitrogen, an element vital to soil health. (Photo by Sarah A. Batterman)

Rapper Pitbull performs onstage during Nickelodeon's celebration of the new Burbank facility on January 11, 2017 in Los Angeles, California. (Photo by Charley Gallay/Getty Images for Nickelodeon)

Human like robots and robotic faces that mimic human expressions are displayed at the annual World Robot Conference at the Beijing Etrong International Exhibition and Convention Center in Beijing, Wednesday, August 16, 2023. (Photo by Ng Han Guan/AP Photo)

Italian actress Sophia Loren attends the Cannes Film Festival in Cannes, France, 1954. (Photo by AGIP/RDA/Getty Images)

A visitor passes behind the sculpture “Puma-Dentist” made with plastic, wax and original heads of a puma and a hind by Austrian artist Deborah Sengl during an exhibition at the art gallery Deschler in Berlin April 15, 2008. (Photo by Fabrizio Bensch/Reuters)

Students rush past the bodies of inmates outside the Croix-des-Bouquets Civil Prison after an attempted breakout, in Port-au-Prince, Haiti, Thursday, February 25, 2021. At least seven people were killed and one injured on Thursday after eyewitnesses told The Associated Press that several inmates tried to escape from a prison in Haiti’s capital. (Photo by Dieu Nalio Chery/AP Photo)

A hot air balloon flies close to the ground in the Jezreel Valley in northern Israel during an international hot air balloon festival October 14, 2014. (Photo by Nir Elias/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.