A walrus kisses a visitor during a sea animal show at the Hakkeijima Sea Paradise aquarium-amusement park complex in Yokohama, southwest of Tokyo, Monday, September 11, 2017. (Photo by Shizuo Kambayashi/AP Photo)

A man transports the carcass of a car on a two- wheeled carriage in a neighborhood in Abobo, a suburb of Abidjan, Côte d’Ivoire on December 1, 2017. (Photo by Issouf Sanogo/AFP Photo)

A rickshaw puller transports passengers through a water-logged street after heavy rain in Kolkata, India on June 26, 2018. (Photo by Rupak De Chowdhuri/Reuters)

Soldiers on exercise in Kenya. The image, by Sergeant Dek Traylor, is among the section winners in the UK Army Photographic Competition 2018. (Photo by Sergeant Dek Traylor/PA Wire Press Association)

Syrian refugee boys play with toy guns at Eminonu district in Istanbul, Turkey, 08 January 2019. (Photo by Sedat Suna/EPA/EFE)

Hindu devotees watch as a 12 meter (40 feet) high statue of Hindu monkey-god Hanuman is washed during Hanuman Jayanti, the birthday of Lord Hanuman in Hyderabad, India, Friday, April 22, 2016. Hanuman is one of the most popular gods in the crowded pantheon of Hindu deities, and devout Hindus ascribe great strength and valor to him. (Photo by Mahesh Kumar A./AP Photo)

Residents watch the ocean waves crash into the water front, after the passage of Hurricane Irma, in Cuba, Sunday, September 10, 2017. (Photo by Ramon Espinosa/AP Photo)

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.