Indian dancers paint their body like tigers as they perform a Tiger dance during the International day of the Tiger in Calcutta, India, July 29, 2015. Students of Calcutta are taking part in an awareness campaign aiming to draw attention to the threats that tigers face due to habitat loss and poaching. (Photo by Piyal Adhikary/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.

This NASA photo shows a United Launch Alliance Atlas V rocket with NASA’s Mars 2020 Perseverance rover onboard as it launches from Space Launch Complex 41 at Cape Canaveral Air Force Station, on July 30, 2020, from NASA’s Kennedy Space Center in Florida. The Perseverance rover is part of NASA’s Mars Exploration Program, a long-term effort of robotic exploration of the Red Planet. (Photo by Joel Kowsky/NASA)

British fashion model Daisy Lowe sent her fans wild with this photo in the second decade of March 2022. Daisy showed off her intimate tattoo as she posed in the high-waisted thong. (Photo by daisylowe/Instagram)

India: A sweeper cleans the side of a road near a replica of the Eiffel Tower amid heavy fog in the early morning in the northern Indian city of Chandigarh January 18, 2010. (Photo by Ajay Verma/Reuters)

Dan Luvisi reimagines beloved animated characters and turns them into grimy, twisted, hideous personas that may have just scarred us of our fondest memories from childhood forever. Photo: “The Cook”. (Photo by Dan Luvisi)

A fisherman with a close bond to cormorants uses the flock of birds to catch big fish in Li river in Guilin, China. The aquatic birds can be seen perching on a bamboo raft before swooping into the calm water to grasp hold of prey. (Photo by Julia Wimmerlin/Solnet News & Photo Agency)