A hot air balloon competition called “Grudziadzkie Zawody Balonowe” is held in Lisie Katy, central-northern Poland, 14 May 2021. The compe​tition is held for the eighteenth time. (Photo by Tytus Zmijewski/EPA/EFE)

A participant wrestles with a pig in the “greased pig contest” at the Festival du Cochon (Pig Festival) in Sainte-Perpetue, Quebec August 8, 2015. (Photo by Christinne Muschi/Reuters)

Several beaches along South Florida's Atlantic coast line were closed after thousands of sharks were seen migrating in the waters. The sharks were migrating from Boca Raton to Jupiter since the beginning of March, marine biologists told NBC Miami. Photo: A spinner shark swims just offshore on Midtown Beach in Palm Beach on Tuesday. (Photo by Jeffrey Langlois/Palm Beach Daily News)

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.

An anti-extradition bill protester throws a stone at a police station in Tseung Kwan O residential district, in Hong Kong, China, August 4, 2019. (Photo by Kim Kyung-Hoon/Reuters)

A woman takes a photo of a mural by Berlin-based street artist Eme Freethinker featuring the likeness of US actor Will Smith (R) slapping US comedian Chris Rock during the Oscars ceremony, in Berlin on March 30, 2022. (Photo by John MacDougall/AFP Photo)

In 2013, the United Nations General Assembly officially designated November 19 as World Toilet Day, which is coordinated by UN-Water in collaboration with governments and partners. Here: An open-air toilet and a hot spring shower are seen in the middle of nowhere on the road to the Krafla geothermal power station and lava fields, near Reykjahlid and Lake Myvatn in northeastern Iceland, on August 19, 2012. (Photo by Mariana Suarez/AFP Photo)

Filipino children frolic next to ships taking shelter inside a seaport in Navotas city, north of Manila, Philippines, 27 August 2019. According to the latest advisory from Philippine Atmospheric Geophysical and Astronomical Services Administration (PAGASA), Tropical Storm Podul intensified from a tropical depression into a tropical storm on August 27, while moving toward Central Luzon with a maximum winds of 65 kilometers per hour and gustiness of up to 80 km/h. (Photo by Francis R. Malasig/EPA/EFE)