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.

The Komodo dragon (Varanus komodoensis) was the most popular species overall based on English language Wikipedia page views. It is the world’s largest lizard, living on the islands of Komodo, Rinca and other smaller islands, and on Flores island in Indonesia. (Photo by Eric Nathan/Alamy)

David Martinez, a divemaster and shark feeder, risks life and limb when he hand feeds tiger sharks at Tiger Beach in the Bahamas in December 2022. (Photo by Caters News Agency)

Workers wearing face masks as a protection against the coronavirus disease (COVID-19) carry roasted pigs, locally known as “lechon”, at a restaurant, in Quezon City, Metro Manila, Philippines, December 21, 2020. (Photo by Lisa Marie David/Reuters)

Miss Amazonas Ileana Marquez kisses her daughter, after winning the Miss Venezuela 2023 pageant, whose winner will participate in the Miss Universe 2024 contest, in Caracas, Venezuela on December 8, 2023. (Photo by Leonardo Fernandez Viloria/Reuters)

Spain's defender #14 Laia Codina celebrates scoring her team's fourth goal during the Australia and New Zealand 2023 Women's World Cup round of 16 football match between Switzerland and Spain at Eden Park in Auckland on August 5, 2023. (Photo by Saeed Khan/AFP Photo)

Revelers dance and shout as they listen to music, in front of the main stage, during the 21st Woodstock Festival in Kostrzyn-upon-Odra, Poland July 31, 2015. An estimated 200,000 people attended the ongoing festival, a brainchild of Polish journalist and social campaigner Jerzy Owsiak, on Friday. Owsiak initiated the event to say thank you to those who donated money to his GOCC charity organisation that delivers medical care for children. (Photo by Kacper Pempel/Reuters)

“On the Li River near Xingping in China, Cormorant fishermen work the waterways before dawn amidst the spectacular limestone towers of the Karst landscape. The birds are trained to fetch fish from the inky depths but not swallow them. The fisherman accepts the fish from the birds who dive back for more. Here, still before dawn, the fisherman and his birds head for home”. (Photo and caption by Neville Jones/2014 Sony World Photography Awards)