North Korean leader Kim Jong Un (3rd R) and wife Ri Sol Ju (4th L) enjoy an art performance given by the Chongbong Band to mark the 70th anniversary of the founding of the Workers' Party of Korea (WPK) in this undated photo released by North Korea's Korean Central News Agency (KCNA) in Pyongyang on October 19, 2015. (Photo by Reuters/KCNA)

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.

“Show us our butts! Mucawana tribe – Angola. In Soba village, the Muhacaona (Mucawana) tribe, perhaps the best place i have visited. They use cow dung and fat to make this so nice haircut, and love the beads. They asked me to make pictures of their backs... and butts to see on the camera screen if everything was perfect!”. (Photo and comments by Eric Lafforgue)

A pilot demonstrates an aircraft manufactured by US-based LIFT Aircraft in front of Osaka Castle in Osaka on March 14, 2023. (Photo by JIJI Press/AFP Phoot)

A handout photo made available by Limex Images of Pete McLeod of Canada (R) and Kirby Chambliss of the United States flying over the city of Kazan prior to the fifth stage of the Red Bull Air Race World Championship in Russia on August 22, 2018. (Photo by Joerg Mitter/EPA/EFE/Limex Images)

Paragliders fly towards the landing area of the “Acro Show” above Lake Geneva in Villeneuve, Switzerland on Sunday, August 26, 2018. (Photo by Valentin Flauraud/Keystone via AP Photo)

Egrets stand on a field as an Egyptian farmer plants rice seedling in Egypt's fertile Delta in Tanta, Algharbeya governorate, 100 km from Cairo, Egypt, 22 June 2022. Egyptian Government reduced the planting of some crops that need a massive amount of irrigation water, while the government said it will reduce the rice agriculture area in Egypt, amid fear the Renaissance Dam project in Ethiopia could affect the amount of River Nile water reaching Egypt. (Photo by Khaled Elfiqi/EPA/EFE)

Boca Juniors' Paraguayan defender Bruno Valdez (bottom) and Nacional's forward Bruno Damiani fight for the ball during the Copa Libertadores round of 16 second leg football match between Argentina's Boca Juniors and Uruguay's Nacional, at La Bombonera stadium in Buenos Aires, on August 9, 2023. (Photo by Juan Mabromata/AFP Photo)