Monkeys climb onto tourists during the annual Monkey Festival in Lopburi province, Thailand on November 26, 2023. (Photo by Chalinee Thirasupa/Reuters)

A vendor works on a Christmas star lantern, locally known as parol, at a street market in Quezon City, Metro Manila, Philippines on November 29, 2023. (Photo by Eloisa Lopez/Reuters)

Scooby performs at halftime of the game between the TCU Horned Frogs and Texas Tech Red Raiders at Ed and Rae Schollmaier Arena in Fort Worth, Texas on January 30, 2024. (Photo by Kevin Jairaj/USA TODAY Sports)

Models prepare backstage before a creation from the Saint Joy by Bian Huizhong during the China Fashion Week in Beijing on March 30, 2023. (Photo by Wang Zhao/AFP Photo)

Rescuers attend an injured fan lying on the field of the Cuscatlan stadium in San Salvador, El Salvador, Saturday, May 20, 2023. At least nine people were killed and dozens more injured when stampeding fans pushed through one of the access gates at a quarterfinal Salvadoran league soccer match between Alianza and FAS. (Photo by Milton Flores/AP Photo)

A plane drops water to put out the fire broke out yesterday in a grassy area in Kizilcahamam district of Ankara and spread to a forest area in Gerede district of Bolu as firefighters, Turkish General Directorate of Forestry teams and officers continue their extinguishing and cooling efforts in the forest fire that is under control on August 22, 2024 in Bolu, Turkiye. (Photo by Emin Sansar/Anadolu via Getty Images)

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)

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.