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.

Local residents dressed in costumes perform during celebrations for the Malanka holiday in the village of Krasnoilsk in the Chernivtsi region of Ukraine, January 14, 2016. The Malanka traditional holiday is more popular in the western regions of the country and is also known as the Old New Year celebrated on January 13 and 14 – St. Basil's and St. Melania's Day, according to the old Julian calendar. During the celebrations, youngsters and adults wear traditional carnival costumes and masks, and visit local houses while singing carols, playing pranks or performing short plays. (Photo by Valentyn Ogirenko/Reuters)

Birds behaviour winner: Land of the Eagle by Audun Rikardsen, Norway. High on a ledge, on the coast near his home in northern Norway, Rikardsen carefully positioned an old tree branch that he hoped would make a perfect golden eagle lookout. To this, he bolted a tripod head with a camera, flashes and motion sensor attached, and built himself a hide a short distance away. From time to time, he left road‑kill carrion nearby. Very gradually – over the next three years – a golden eagle got used to the camera and started to use the branch regularly to survey the coast below. (Photo by Audun Rikardsen/2019 Wildlife Photographer of the Year)

Lebanese university students wearing municipality police costume regulate the traffic in the village of Brummana, east Beirut, Lebanon, 23 June 2018. The touristic town of Brummana is making a daring move in anticipation of the crowded summer season, by forming a group of young policewomen wearing mini shorts to regulate the traffic. (Photo by Wael Hamzeh/EPA/EFE)

“Maho Beach is a beach on the Dutch side of the Caribbean island of Saint Martin, in the country of Sint Maarten. It is famous for the Princess Juliana International Airport adjacent to the beach. Arriving aircraft must touch down as close as possible to the beginning of Runway 10 due to the short runway length of 2,180 metres (7,150 ft), resulting in aircraft on their final approach flying over the beach at minimal altitude”. – Wikipedia

Photo: “AirFrance Boeing 747 landing in St. Maarten”. (Photo by Aurimas)

Bloodthirsty by Thomas P. Peschak, Germany/South Africa — winner, Behaviour: birds. When rations run short on Wolf Island, in the remote northern Galápagos, the sharp-beaked ground finches become vampires. Their sitting targets are Nazca boobies and other large birds. The finches rely on a scant diet of seeds and insects, which regularly dries up, so they drink blood to survive. ‘I’ve seen more than half a dozen finches drinking from a single Nazca booby,’ says Tom. Rather than leave their nests the boobies tolerate the vampires, and the blood loss doesn’t seem to cause permanent harm. (Photo by Thomas P. Peschak/2018 Wildlife Photographer of the Year)

In this January 23, 2015 photo, Guillermo Luna Martinez, 36, carries freshly painted piñatas representing Disney's Frozen snowman character Olaf downstairs to where his wife Elvia Vicente Albarran will use paper to craft the character's eyes, teeth, and distinctive tuft of hair, at the family's workshop in the Iztapalapa neighborhood of Mexico City. Though Luna and his wife have chosen to work in the family business, they plan to let their children, Guillermo, 10, and Melissa, 9, decide for themselves. “Who knows if the business will last forever”, said Luna, “I'd prefer that they study and get a career, for them to have a better future”. (Photo by Rebecca Blackwell/AP Photo)