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.

Performers are reflected in a displayed vehicle before going onto the stage during the Auto China 2016 auto show in Beijing, China, April 29, 2016. (Photo by Damir Sagolj/Reuters)

Fighting Infections (single image) | Fighting Pandemic by Sudipto Das. “It’s exhausting. A tram conductor in Kolkata, India, wears protective clothing from head to toe even in the heat of a summer afternoon. This was when restrictions were easing after India’s first Covid-19 lockdown – public transport was running, but staff were advised to suit up like this. We’ve all grown used to saluting the efforts of healthcare workers, but plenty of other people in public-facing jobs have performed gruelling duties too to keep people safe”. (Photo by Sudipto Das/Wellcome Photography Prize 2021)

Models wearing creations by Philippines designer Nicole Santos wait backstage during the Thailand Fashion Week 2022 in Bangkok, Thailand, 30 June 2022. The Thailand Fashion Week showcases men's and women's Autumn/Winter 2022-2023 collections from both established and emerging brands across Haute-Couture, Ready-To-Wear, Avant-Garde, Accessories and Footwear on 29 and 30 June 2022. (Photo by Diego Azubel/EPA/EFE/Rex Features/Shutterstock)

Thomas jumps into the water from a spring board at a public swimming pool in Mengen, Germany, 28 August 2016. (Photo by Thomas Warnack/EPA)

21 year-old Chanel Tapper, with the amazing tongue and 35 year-old Aevin Dugas, with the beautiful hair was certified as world record breakers for the world’s longest tongue and the world’s biggest afro in the Guinness Book of World Records. (Photo by Guinness World Records)

Belarussian policemen detain a woman in central Minsk on August 11, 2020. Thousands of opposition supporters who also protested the results met with a tough police crackdown in Minsk and several other Belarusian cities for two straight nights. (Photo by Uladz Hrydzin/Radio Free Europe/Radio Liberty)

Pigeons fly out from the mouth of a giant Buddha statue at Wat Nam Daeng Buddhist temple in Chachoengsao province, east of the Thai capital Bangkok, on October 11, 2020. (Photo by Mladen Antonov/AFP Photo)