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.

Libyan forces allied with the U.N.-backed government fire weapons during a battle with IS fighters in Sirte, Libya, July 21, 2016. (Photo by Goran Tomasevic/Reuters)

A woman tries a swing in front of a screen featuring New York scenes during the new Air France Exhibition called “Air France, France is in the Air” in New York June 25, 2014. (Photo by Timothy A. Clary/AFP Photo)

Anissa Barbato from New York looks out over the city from the Edge, the highest outdoor sky deck in the Western Hemisphere on September 2, 2020 as it reopened to the public in New York. Rising 1,131 feet in the air from the heart of Hudson Yards it offers 360-degree views of New York Citys iconic skyline from the 100th floor outdoor viewing. (Photo by Timothy A. Clary/AFP Photo)

A model wears a face mask to help prevent the spread of the coronavirus, designed by Iraqi designer Ziad Tariq at his workshop in Basra, Iraq, Monday, July 20, 2020. (Photo by Nabil al-Jurani/AP Photo)

Nina Bahinskaya, 73, poses for a photo holding an old Belarusian national flag at an entrance of her apartment building in Minsk, Belarus, Thursday, September 10, 2020. The 73-year-old former geologist has become one of the most recognizable faces of Belarus protests, fearlessly waving a huge opposition's red-and-white flag in front of riot police. (Photo by AP Photo/Stringer)

People assist a woman who was exposed to tear gas by pouring milk over her face after police fired tear gas and water canon to try and disperse protesters outside Parliament on November 17, 2020 in Bangkok, Thailand. The demonstrators gathered outside parliament, on Tuesday, as the Thai government met to discuss amendments to the country's constitution. (Photo by Lauren DeCicca/Getty Images)

A boy wearing a dress-up costume to mark the upcoming Jewish holiday of Purim, which is a celebration of the Jews' salvation from genocide in ancient Persia, walks on a street in the ultra-Orthodox Jewish neighbourhood of Mea Shearim in Jerusalem on February 24, 2021. (Photo by Ammar Awad/Reuters)