A young Iranian woman walks in Tehran on June 14, 2021, ahead of the June 18 presidential elections. Iran is gearing up for a presidential election on June 18 but many young people are more focussed on the daily struggle to survive and their dreams for the future. Jobs are scarce in a recession-hit economy battered by sanctions, a crisis exacerbated by the region's worst outbreak of the Covid pandemic. (Photo by Atta Kenare/AFP Photo)

Visitors look at a plastinated human body during the “Body Worlds” exhibition by German anatomist Gunther von Hagens at a pavilion of the Exhibition of Achievements of National Economy (VDNKh) in Moscow, Russia on March 24, 2021. Head of Russian Investigative Committee Alexander Bastrykin ordered a probe of the exhibition after it sparked outrage among conservative religious groups and public figure. (Photo by Evgenia Novozhenina/Reuters)

People play ice hockey in front of the Olympic Tower near the National Stadium at Olympic Park on January 13, 2022 in Beijing, China. Playing host to the 2022 Winter Olympics has boosted the popularity of winter sports and outdoor activities in many parts of China, with the government pouring billions of dollars into developing programs, athletes, and fans. With more outdoor skating rinks, ski resorts, and other activities luring people outside, the ice and snow sports boom has created nearly 350 million winter sport enthusiasts since Beijing"u2019s successful Games bid in 2015, according to officials. China is seeking to become a winter sports destination as the global snow sports industry eyes growth in the world second largest economy. (Photo by Kevin Frayer/Getty Images)

A dog dives during a pet dog swimming contest at the Taoyuan Pet Center on July 31, 2005 in Chengdu of Sichuan Province, southwest China. Over 30 dogs have attended the match. According to state media, with the country's pet population growing fast, analysts predict that the market potential for the “pet economy” in China could reach a minimum of RMB 15 billion (about USD 1.85 billion). (Photo by China Photos/Getty Images)

A Muslim woman prays at the Al Meroz hotel in Bangkok, Thailand, August 29, 2016. Predominately Buddhist Thailand has opened its first halal hotel as hopes to attract more Muslim visitors and boost one of the few bright spots in its economy. (Photo by Chaiwat Subprasom/Reuters)

A humanoid robot works side by side with employees in the assembly line at a factory of Glory Ltd., a manufacturer of automatic change dispensers, in Kazo, north of Tokyo, Japan, July 1, 2015. Japanese firms are ramping up spending on robotics and automation, responding at last to premier Shinzo Abe's efforts to stimulate the economy and end two decades of stagnation and deflation. (Photo by Issei Kato/Reuters)

Central Bangkok and the Chao Phraya River are seen from an abandoned skyscraper in Bangkok April 19, 2015. The abandoned building, known as Satorn Unique, dubbed the “ghost tower” was destined to become one of Bangkok's most luxurious residential addresses but construction was never completed as the Thai economy was hit during the 1997 Asian Financial Crisis. Now, many travellers visit and explore 49-storey skyscraper. (Photo by Athit Perawongmetha/Reuters)

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.