Fire runners in devil costumes gather to enlighten their stick mounted firecrackers during the “Correfocs” at the “Fiesta Major” of the Sagrada Familia in Barcelona, Spain on April 15, 2023. (Photo by Matthias Oesterle/Alamy Live News)

Indian School children's in a traditational attire of a characters of Indian epic Ramayan, on the eve of children's day celebration at cubbon park, in Bangalore, India, 13 November 2016. Children's day (also known as Bal Divas), in India is celebrated every year on 14th of November to increase the awareness of people towards the rights, care, and education of children. Many schools hold activities and allow students to have fun and attend their classes in coloured dresses. (Photo by Jagadeesh N.V./EPA)

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.

View at one of the sculptures by Swiss artist H.R. Giger during the opening of the Ars Electronica 2013 exhibition “HR Giger. The Art of Biomechanics” in Linz, Austria, 04 September 2013. (Photo by EPA/RUBRA)

Models wait backstage before the opening show for China Fashion Week, featuring Finnish outdoor gear brand Halti, in Beijing, Thursday, March 20, 2025. (Photo by Ng Han Guan/AP Photo)

A general view of a beauty salon on July 8, 2023 in Kabul, Afghanistan. This week, a Taliban spokesman said the group, which regained control of Afghanistan in 2021, was ordering the closure of beauty salons because they offered services forbidden by Islam. (Photo by Nava Jamshidi/Getty Images)

Traffic police stand at the side of a road in Pyongyang on November 25, 2016. (Photo by Ed Jones/AFP Photo)

A dog at the Zoozashchita-NN veterinary clinic in Nizhny Novgorod, Russia on February 19, 2021. On February 13, 13 stray dogs with bright blue fur were found and caught at the Dzerzhinskoye Steklo (Dzerzhinsk Glass) factory producing acrylic glass and prussic acid in the city of Dzerzhinsk. The dogs' fur tested positive for the Prussian blue pigment; now the dogs are under supervision at the Zoozashchita-NN vet clinic in Nizhny Novgorod. (Photo by Mikhail Solunin/TASS)