Orthodox believers participate in a procession in St. Petersburg, Russia, 12 September 2022. The procession marks the 298th anniversary of the transfer of the relics of St. Alexander Nevsky, who is considered to be a heavenly protector of St. Petersburg. (Photo by Anatoly Maltsev/EPA/EFE)

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.

Leopard seal chasing a Gentoo penguin in Antarctica. This image wins the gold prize in the behaviour – mammals category, and the grand prize of World Nature Photographer of the Year. (Photo by Amos Nachoum/World Nature Photography Awards)

Colored Pencil and Origami Landscapes: Ivanova's version of the popular Snake game features a chain-link origami snake chasing a butterfly. (Photo by Victoria Ivanova)

A tern chased away a ghost crab that was threatening its chicks at a beach near Fort Myers, Florida in the last decade of June 2023, before feeding them with freshly caught fish. (Photo by Judy Rogero/Solent News)

Double tornadoes, lightning storms and rotating supercells – this is what it's like to chase storms for a year. These dramatic images show apocalyptic weather throughout 2014 from a lightning storm to a pair of rainbows. Roger Hill, 57, has been chasing storms in the United States for thirty years and runs a tour operation with his wife Caryn. Here: a hailstorm rolls over fields, on July 22, 2014, in South Dakota. (Photo by Roger Hill/Barcroft Media)

Copperhead ridden by Harry Cobden falls during the RSA Insurance Novices' Chase (Grade 1) at Cheltenham Racecourse on March 11, 2020 in Cheltenham, England. (Photo by Tom Jenkins/The Guardian)

An Arizona Diamondbacks fan catches a foul ball during the seventh inning against the Cincinnati Reds at Chase Field on June 14, 2022 in Phoenix, Arizona. (Photo by Norm Hall/Getty Images)