A participant tries to stay warm during the Macy's Thanksgiving Day Parade in Manhattan,New York, U.S., November 22, 2018. (Photo by Brendan McDermid/Reuters)

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.

“Family disagreement”. (Photo by Vlado Pirsa/Comedy Wildlife Photo Awards 2019)

A Bull Frog hops around as Carlos Costly #13 of Honduras brings the ball up against the USA at Sun Life Stadium on October 8, 2011 in Miami Gardens, Florida. (Photo by Marc Serota/Getty Images)

Corey Arnold is a fine art photographer and a commercial fisherman, working the stormy waters of the Bering Sea by Alaska. His latest work documents life in this remote wilderness, both at sea and on the shore, capturing trawlers, foxes, eagles and the grandeur of the scenery. “Aleutian Dreams” can be seen at Charles A Hartman Fine Art in Portland, Oregon, until 27 May. Here: “Roadside Friend”. (Photo by Corey Arnold/Charles A. Harman Fine Art/The Guardian)

An artist performs in water during a dress rehearsal for “Amaluna”, a show by Cirque du Soleil, at the Royal Albert Hall in London, Britain January 15, 2016. (Photo by Dylan Martinez/Reuters)

Sеxy women kissing in bed. (Photo by Sakkmesterke/Getty Images)

Nine year old girl Barsati reacts while walking on a tightrope in Mumbai on February 11, 2014. Barsati, and her younger brother Rajababu, (4) earn an average of around 2000 rupees (32 dollars) per day from pedestrians and tourists performing various acts on the tightrope near the city's iconic landmark Gateway of India. (Photo by Indranil Mukherjee/AFP Photo)