Coaches of the North-East Express passenger train that derailed late Wednesday near Raghunathpur railroad station in Buxar district of Bihar state, India, Thursday, October 12, 2023. The train was on its way to Assam state from New Delhi. (Photo by Aftab Alam Siddiqui/AP Photo)

Three Siberian tiger cubs meet visitors at Yangzhou Zoo in Yangzhou City, east China's Jiangsu Province, on 27 June, 2024. (Photo by Splash News and Pictures)

Two people ride a motorcycle as a Taiwanese Air Force Mirage 2000 fighter jet approaches for landing at an air force base in Hsinchu in northern Taiwan on May 23, 2024. China on May 23 encircled Taiwan with naval vessels and military aircraft in war games aimed at punishing the self-ruled island after its new president vowed to defend democracy. (Photo by Yasuyoshi Chiba/AFP Photo)

The trailer of an articulated lorry juts into the air after the vehicle came off a bridge on Interstate 81 southbound in Butler Township in Pennsylvania, US on November 9, 2021. (Photo by Sean McKeag/AP Photo)

Several beaches along South Florida's Atlantic coast line were closed after thousands of sharks were seen migrating in the waters. The sharks were migrating from Boca Raton to Jupiter since the beginning of March, marine biologists told NBC Miami. Photo: A spinner shark swims just offshore on Midtown Beach in Palm Beach on Tuesday. (Photo by Jeffrey Langlois/Palm Beach Daily News)

Tami Varma, right, and her brother Robin, the grandchildren of Devendra Varma, a scholar of English gothic tales and an expert in vampire lore, pose in coffins at the Bran Castle, in Bran, Romania, Monday, October 31, 2016. A Canadian brother and sister are passing Halloween night curled up in red velvet coffins in the Transylvanian castle that inspired the Dracula legend, the first time in 70 years anyone has spent the night in the gothic fortress, after they bested 88,000 people who entered a competition hosted by Airbnb to get the chance to dine and sleep at the castle in Romania. A portrait of medieval prince Vlad the Impaler is placed on the wall. (Photo by Vadim Ghirda/AP Photo)

In this aerial view the officers' building and an auditorium stand at the former Soviet military base on January 26, 2017 in Wuensdorf, Germany. Wuensdorf, once called “The Forbidden City”, was the biggest base for the Soviet armed forces in communist East Germany from 1945 until the last Soviet troops left in the early 1990s following the end of the Cold War and the reunification of Germany. (Photo by Sean Gallup/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.