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.

Alessandra Perilli, of San Marino, competes during the trap women's qualification at the 2016 Summer Olympics in Rio de Janeiro, Brazil, Sunday, August 7, 2016. (Photo by Hassan Ammar/AP Photo)

People struggle with umbrellas while walking against strong wind, as Typhoon Koinu approaches, in Hong Kong, China on October 8, 2023. (Photo by Tyrone Siu/Reuters)

Golden State Warriors guard Stephen Curry (30) is flipped upside down after a play during the second quarter against the Sacramento Kings at Golden 1 Center on November 28, 2023 in Sacramento, California. (Photo by Sergio Estrada/USA TODAY Sports)

Benfica's Jessica Silva, right, fights for the ball with Barcelona's Ingrid Syrstad Engen during the women's Champions League group A soccer match between SL Benfica and FC Barcelona at the Benfica Campus in Seixal, outside Lisbon, Wednesday, January 31, 2024. (Photo by Armando Franca/AP Photo)

FC Barcelona's Catalina Coll and Lucy Bronze in action with Olympique Lyonnais' Lindsey Horan during their women's Champions League final in Bilbao, Spain on May 25, 2024. (Photo by Violeta Santos Moura/Reuters)

“Magician David Blaine's latest stunt boasts lots of high-voltage snap, crackle and pop – but experts say he'll be safe from electrocution as long as he wears his chain-mail suit and metal headgear”. – NBC News. Photo: Blaine stands inside the apparatus, surrounded by a million volts of electric currents streamed by tesla coils. The stunt, sponsored by Intel, is the latest of daredevil endeavors by the magician whose previous stunts included being encased in ice for over 60 hours in Times Square, on October 5, 2012. (Photo by John Minchillo/Associated Press)

“Dover Castle is a medieval castle in the town of the same name in the English county of Kent. It was founded in the 12th century and has been described as the “Key to England” due to its defensive significance throughout history. It is the largest castle in England.

The outbreak of the Second World War in 1939 saw the tunnels converted first into an air-raid shelter and then later into a military command centre and underground hospital. In May 1940, Admiral Sir Bertram Ramsey directed the evacuation of French and British soldiers from Dunkirk, code-named Operation Dynamo, from his headquarters in the cliff tunnels”. – Wikipedia

Photo: The Repeater Station in the subterranean tunnels underneath Dover Castle, which has been restored by English Heritage for a public exhibition on June 3, 2011 in Dover, England. The evacuation of allied soldiers from Dunkirk was masterminded and co-ordinated from the secret command and control centre in the tunnels deep below the castle. (Photo by Matthew Lloyd/Getty Images)