A woman reacts as she inspects damages at Al Shifa Hospital after Israeli forces withdrew from the hospital and the area around it following a two-week operation, amid the ongoing conflict between Israel and Hamas, in Gaza City on April 1, 2024. (Photo by Dawoud Abu Alkas/Reuters)

Water vapour cascades down the Gold Buddha Mountain after a rainfall, drawing large crowds of visitors, on May 13, 2024 in Chongqing, China. (Photo by Qu Mingbin/VCG via Getty Images)

American actress Shelley Duvall poses for photographers at the 30th Cannes Film Festival in France, May 27, 1977. Duvall, whose wide-eyed, winsome presence was a mainstay in the films of Robert Altman and who co-starred in Stanley Kubrick's “The Shining”, has died. She was 75. (Photo by Jean-Jacques Levy/AP Photo)

Firefighters watch as an air tanker drops retardant while battling the Ferguson fire in the Stanislaus National Forest, near Yosemite National Park, California on July 21, 2018. A fire that claimed the life of one firefighter and injured two others near California's Yosemite national park has almost doubled in size in three days, authorities said Friday. (Photo by Noah Berger/AFP Photo)

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.

A Toy Poodle is groomed at the benching area before competition at the 139th Westminster Kennel Club's Dog Show in the Manhattan borough of New York February 16, 2015. (Photo by Mike Segar/Reuters)

A demonstrator confronts a police officer outside the 18th District Police station during a rally after the death of Walter Wallace Jr., a Black man who was shot by police in Philadelphia, Pennsylvania, U.S., October 27, 2020. (Photo by Bastiaan Slabbers/Reuters)