Members of the Albert Battery perform a gun salute during the Anzac Day dawn service held by the Currumbin RSL on the Gold Coast in Currumbin, Australia, 25 April 2016. The Anzac day marks the landing of the Australian and New Zealand Army Corps (Anzac) troops at Gallipoli in what is today Turkey during WWI. World War One, also called the Great War, according to official statistics cost more than 37 million military and civilian casualties between 1914 and 1918. (Photo by Glenn Hunt/EPA)

Mosha, the elephant that was injured by a landmine, has her prosthetic leg attached at the Friends of the Asian Elephant Foundation in Lampang, Thailand, June 29, 2016. Mosha was 7 months old when she stepped on a land mine near Thailand’s border with Myanmar and lost a front leg. That was a decade ago... (Photo by Athit Perawongmetha/Reuters)

Photographer Carlos Barria holds a print of a photograph he took in 2005, as he matches it up at the same location 10 years on, in Lafitte, south of New Orleans, United States, August 16, 2015. The print shows Tyler Teal cleaning up his home, September 14, 2005, after Hurricane Katrina struck. In 2005, Hurricane Katrina triggered floods that inundated New Orleans and killed more than 1,500 people as storm waters overwhelmed levees and broke through floodwalls. (Photo by Carlos Barria/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.

A competitor dressed up as Santa Claus jumps into the sea during the 102nd Barcelona Traditional Christmas Swimming Cup at the Old Harbour of Barcelona on December 25, 2011 in Barcelona, Spain. (Photo by David Ramos/Getty Images)

Gulparai, 12, (L) smokes heroin along side her mother Sabera and brother Zaher, 14, (R) August 27, 2007 in Kabul, Afghanistan. (Photo by Paula Bronstein/Getty Images)

Participants at the Dubai Run at Sheikh Zayed Road in Dubai, United Arab Emirates on November 26, 2021. (Photo by Ruel Pableo for The National)