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.

In this Saturday, February 18, 2017 photo, revelers take part in the “Guanabara Pearl” carnival street party on Paqueta Island in Rio de Janeiro, Brazil. Merry makers ferried across Guanabara Bay to Paqueta Island for the parade. (Photo by Mauro Pimentel/AP Photo)

A woman wears false flag eyelashes during the St Patrick's day parade through Dublin city centre on St Patrick's day, on March 17, 2013. (Photo by Julien Behal/PA Wire)

A health worker administers a dose of the Sinovac COVID-19 vaccine to a worker in a local entertainment venue area where a new cluster of COVID-19 infections were found in Bangkok, Thailand, Wednesday, April 7, 2021. Officials in Thailand’s capital have ordered a two-week closure of all entertainment venues in three districts to try to limit the spread of the coronavirus from nightspots there. (Photo by Sakchai Lalit/AP Photo)

Women practice “katte samu”, a rural traditional self-defence martial art during a workshop organised by the The Department of Language, Art and Culture of Telangana state for the upcoming International Women Day in Hyderabad, on March 6, 2020. (Photo by Noah Seelam/AFP Photo)

Wearing a mariachi hat, candidate Clara Brugada, who is running as a delegation leader under the ruling party Morena, smiles as she greets supporters on the last day of campaigning ahead of the June 6 mid-term elections, in the Iztapalapa borough of Mexico City, Wednesday, June 2, 2021. (Photo by Marco Ugarte/AP Photo)

An Orthodox believer kisses an icon during a pilgrimage celebrating the icon of St. Nicholas in the village of Velikoretskoye in Kirov Region, Russia on June 6, 2021. At least 17 thousand pilgrims, loaded with backpacks and some of them barefoot, took part in a five-day and 150-kilometer-long journey from Kirov to the village of Velikoretskoye, according to the local media. (Photo by Alexey Malgavko/Reuters)

Lily Nguyen of Jessop, from Maryland, leaps up in the air as a friend takes her photo in front of cherry blossoms which have reached their peak bloom, along the Tidal Basin, in Washington, D.C., U.S., March 21, 2022. (Photo by Kevin Lamarque/Reuters)