A soldier eats ice cream as she visits a zoo in Pyongyang, North Korea, September 12, 2018. (Photo by Danish Siddiqui/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.

Hundreds of people pack the Canaveral national seashore's Playalinda Beach as a United Launch Alliance Atlas V rocket, carrying a U.S. Navy communications satellite, lifts off from Complex 41 at the Cape Canaveral Air Force Station, Friday, June 24, 2016, in Cape Canaveral, Fla. The satellite is designed to significantly improve ground communications for U.S. forces on the move. (Photo by Craig Rubadoux/Florida Today via AP Photo)

A motorist drives a car overloaded with vegetables and fruit on a street in Yaounde on July 25, 2022, prior to the French president's visit. (Photo by Ludovic Marin/AFP Photo)

A woman dries chili peppers in the sun at a village in Wuyuan County, Jiangxi province, China July 21, 2017. (Photo by Reuters/China Stringer Network)

Barber Herman Mulyana (R) gives a haircut to a customer while wearing protective attire made from plastic garbage bags at a barbershop in Bogor, Indonesia, 06 April 2020. The Trade Ministry of Indonesia issued a regulation temporarily recinding all requirements for the import of protective gear and medical equipment, to counter shortages of many items used to treat COVID-19 patients and prevent the further spread of the disease. (Photo by Adi Weda/EPA/EFE)

A man makes traditional candy “Matang” in preparation for the upcoming Chinese Lunar New Year in Yuqing County, Zunyi, Guizhou Province, China, January 18, 2016. (Photo by Reuters/China Daily)

Performer Zhang Yashu from a Chinese ballet company perform during a photo shoot in front of the Australia's iconic landmarks Opera House (L) and Habour Bridge in Sydney on February 17, 2014. One of China's celebrated dance campanies is bringing one of the country's biggest ballet production to Australia for a series of performances in Sydney and Melbourne. (Photo by Saeed Khan/AFP Photo)