Children enjoy and participate in a traditional street race of “carruchas”, the name for makeshift wooden cars in Caracas, Venezuela, Saturday, December 18, 2021. Children enjoyed the race marking 10 years of persevering this tradition. (Photo by Ariana Cubillos/AP Photo)

Andrew Parkinson, animal behaviour category winner: Crepuscular Contentment, Derbyshire. “In 15 years of working with badgers I’ve never seen a badger sit out in the open to have a scratch. I was sat concealed behind a tree and downwind so it was especially nice that the badger had his back to me, demonstrating just how inconspicuous and inconsequential my presence was”. (Photo by Andrew Parkinson/British Wildlife Photography Awards 2017)

Medics carry an injured at the explosion site in the busy center of Turkish capital, Ankara, Turkey, Sunday, March 13, 2016. The explosion is believed to have been caused by a car bomb that went off close to bus stops. News reports say the large explosion in the capital has caused several deaths and many casualties. (Photo by AP Photo)

The Komodo dragon (Varanus komodoensis) was the most popular species overall based on English language Wikipedia page views. It is the world’s largest lizard, living on the islands of Komodo, Rinca and other smaller islands, and on Flores island in Indonesia. (Photo by Eric Nathan/Alamy)

The Forth Bridge is engulfed by mist on one of the coldest days of the year, on December 12, 2022, in Edinburgh, Scotland. (Photo by Ken Jack/Getty Images)

Several beaches along South Florida's Atlantic coast line were closed after thousands of sharks were seen migrating in the waters. The sharks were migrating from Boca Raton to Jupiter since the beginning of March, marine biologists told NBC Miami. Photo: A spinner shark swims just offshore on Midtown Beach in Palm Beach on Tuesday. (Photo by Jeffrey Langlois/Palm Beach Daily News)

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.