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.

Thierry Reverdi, owner of the Dreamdoll company, adjusts the sunglasses of a silicone dream doll at their workshop in Duppigheim near Strasbourg, December 2, 2014. The realistic silicone s*x dolls can be ordered from a catalogue based on four hair and eye color models for a base price of 5,500 euros ($6,150). The dolls weigh around 40 kilos due to a lightweight aluminum structure and take a week to construct. The company of three employees produces some one hundred custom-made silicone s*x dolls a year, mainly for European customers. (Photo by Vincent Kessler/Reuters)

A policewoman uses a tissue during a protest to mark the International Day for the Elimination of Violence Against Women, in Mexico City, Mexico on November 25, 2021. (Photo by Raquel Cunha/Reuters)

A snowboarder wears a protective cushion at the Thaiwoo ski resort in Zhangjiakou close to venues for the Winter Olympics Beijing 2022, Hebei province, China, November 20, 2021. China hopes hosting the Games will springboard the country towards becoming a winter sports destination and will help deliver on a target set by President Xi Jinping to get 300 million Chinese involved in winter sports, with an aim to build a 1 trillion yuan ($157 billion) industry. (Photo by Thomas Peter/Reuters)

A falla damaged by yesterday's heavy rains is pictured during the Fallas festival in Valencia on September 2, 2021. In Valencia, yesterday's deluge of water disturbed the organization of the Fallas, the major festival in the region featuring parades of floats and giant cardboard sculptures, postponed from March to September due to the pandemic. (Photo by Jose Jordan/AFP Photo)

A brown bears cools off in a pool at the bear sanctuary near the village of Mramor, on August 18, 2020. The bear sanctuary was closed for visitors on August 18, as part of safety measures to curb the spread of the COVID-19 (novel coronavirus) disease. (Photo by Armend Nimani/AFP Photo)

Buddy Mae Walker (R), 4, looks at herself in the mirror while trying on a child respirator provided by the non-profit TeamRaccoonPDX on October 6, 2020 in Portland, Oregon. We told them their grandparents sent them space suits to keep them safe, Jessica Walker said of the respirators, which the family sought out after police used tear gas near their residential street. (Photo by Nathan Howard/Getty Images)

A view of a large poster depicting Russian opposition leader Alexei Navalny behind bars with a dove freeing him from detention, by an unidentified street artist known as Harry Greb, in downtown Rome, Italy, 25 January 2021. Navalny was detained after his arrival to Moscow from Germany on 17 January 2021. A Moscow judge on 18 January ruled that he will remain in custody for 30 days following his airport arrest. Navalny urged Russians to take to the streets to protest against President Putin's rule. (Photo by Fabio Frustaci/EPA/EFE)