A woman looks at an artwork during the preview of the Art Paris 2020 held at the Grand Palais in Paris, France, September 9, 2020. Originally scheduled for April, Art Paris, France's second-biggest modern and contemporary art fair, opens its door to the public from Sept. 10 to 13. (Photo by Chine Nouvelle/SIPA Press/Rex Features/Shutterstock)

Bystanders look at MV Wakashio bulk carrier that had run aground and from which oil is leaking near Blue Bay Marine Park in south-east Mauritius on August 6, 2020. The carrier, belonging to a Japanese company but Panamanian-flagged, ran aground on July 25 and its crew was evacuated safely. The ship was empty at the time but was carrying 200 tonnes of diesel and 3,800 tonnes of bunker fuel, according to the local press. (Photo by Dev Ramkhelawon/L'Express Maurice/AFP Photo)

A young man “painting” the Eiffel Tower. (Photo by Keystone/Getty Images). 9th May 1970

A groom leads his horse in the equine pool after working out on the track, during early morning workouts for the upcoming Derby race in Mumbai January 29, 2015. (Photo by Danish Siddiqui/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.

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)

A boy rides on a snow wagon towed by a robot dressed as a Teddy bear, which only moves forward by moving its legs, during the Ice and snow carnival at Taoranting park in Beijing February 9, 2015. (Photo by Kim Kyung-Hoon/Reuters)

A participant in the Crazy Races extreme sports game competes in the cross-country obstacle race in Ufa, Russia on September 21, 2015. (Photo by TASS/Barcroft Media)