Plebes form a human pyramid to place an upperclassman hat atop the 21-foot vegetable shortening-covered Herndon Monument, a tradition marking the end of their plebe year at the U.S. Naval Academy in Annapolis, Maryland, U.S., May 23, 2022. (Photo by Kevin Lamarque/Reuters)

Finding just the right spot above the clouds at Camp 1 on Ama Dablam, Danuru Sherpa uses his iPhone to catch up with friends and family. Even at 18,500 feet (5,654 meters), climbers here can check their email and other dispatches from the world below. (Photo by Aaron Huey/National Geographic)

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.

Enthusiast Desirae Hepp, dressed as "Immortan Joe," poses for a portrait during Wasteland Weekend event in California City, California September 26, 2015. The four-day event has a post-apocalyptic theme and is inspired by the Mad Max movie franchise. (Photo by Mario Anzuoni/Reuters)

Singer Rihanna prepares for a photoshoot with photographer Annie Leibovitz in Havana, Cuba, May 28, 2015. (Photo by Reuters/Stringer)

Model Heidi Klum in front of Concorde jet after arriving for Victoria's Secret fashion show at Cannes Film Festival on May 16, 2000. (Photo by Marion Curtis/DMI/The LIFE Picture Collection/Getty Images)

(L-R) American rappers Doja Cat and Tyga perform on the Coachella stage during the 2022 Coachella Valley Music And Arts Festival on April 24, 2022 in Indio, California. (Photo by Amy Sussman/Getty Images for Coachella)

Belgium's Crown Princess Elisabeth, center, marches past the Royal tribune with cadets of the military school during the National Day parade in Brussels, Wednesday, July 21, 2021. Belgium celebrates its National Day on Wednesday in a scaled down version due to coronavirus, COVID-19 measures. (Photo by Olivier Matthys/AP Photo)