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.

In this June 20, 2015 photo, Niberta Galvez uses the bottom half of his shirt to collect coca leaves in Samugari, Peru. Coca farmers were among the locals who, in 1984, formed citizen militias to help the military beat back Shining Path rebels, reducing them to a small group of fewer than 500 who now are deeply involved in drug trafficking. (Photo by Rodrigo Abd/AP Photo)

Tsunami, an eleven year old female Sumatran Orangutan eats a fruit platter during her birthday celebration at the National Zoo Ape Center in Kuala Lumpur, Malaysia, Thursday, December 31, 2015. (Photo by Manan Vatsyayana/AFP Photo)

Rapper Destiny Nicole Frasqueri, known professionally as Princess Nokia performs during the Coachella Valley Music and Arts Festival held at the Empire Polo Club in Indio, California, U.S., April 22, 2022. (Photo by Maria Alejandra Cardona/Reuters)

A fuzzy caterpillar on a basil plant in west Bengal, India on December 25, 2023. The caterpillar’s defence system is its hair, which has microscopic barbs that break off easily in the skin of would-be predators. (Photo by Soumyabrata Roy/NurPhoto/Rex Features/Shutterstock)

A handout photo made available by Indonesia's Center for Volcanology and Geological Hazard Mitigation shows hot lava spewing from Mount Ibu in North Maluku province, Indonesia, 04 July 2024 (issued 05 July 2024). The Center for Volcanology and Geological Disaster Mitigation (PVMBG) advises the community around Mount Ibu and visitors not to carry out activities within a radius of 2.0 kilometers and a sectoral expansion of 5 kilometers towards the crater opening in the northern part of the active crater of Mount Ibu. (Photo by PVMBG/EPA)

Wrestlers perform at an all female wrestling event in London. England on August 17, 2017. (Photo by Neil Hall/Reuters)

A demonstrator confronts a police officer outside the 18th District Police station during a rally after the death of Walter Wallace Jr., a Black man who was shot by police in Philadelphia, Pennsylvania, U.S., October 27, 2020. (Photo by Bastiaan Slabbers/Reuters)