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.

“Grit and Glamour”, a retrospective of the late British photographer Elsbeth Juda, who fled Nazi occupation and came to England in 1933, is at the Jewish Museum, in London, until July 1, 2018. Here: Shelagh Wilson, Copacabana beach, Rio de Janeiro, 1951. (Photo by Elsbeth Juda Archive/Victoria and Albert Museum)

A model has her hair done backstage before the Taoray Wang fashion show during New York Fashion Week in New York, New York, 09 February 2019. New York Fashion Week for designer's autumn and winter lines is being held from 06 to 13 February 2019. (Photo by Peter Foley/EPA/EFE)

A ballet dancer stretches backstage during Nacho Duato's “The Nutcracker” at the Mikhailovsky Theatre in St. Petersburg, Russia November 21, 2015. For theatregoers in St Petersburg, Nacho Duato's “The Nutcracker” demonstrates the global appeal of a Christmas classic. When the curtain rises at the Mikhailovsky Theatre, among the oldest opera and ballet houses in Russia, it's the culmination of hundreds of hours of toil and sweat by dancers, costume makers, set designers and musicians playing the famous score by Pyotr Tchaikovsky. (Photo by Grigory Dukor/Reuters)

An ice covered entrance door to the international gene bank Svalbard Global Seed Vault (SGSV) near Longyearbyen on Spitsbergen, Norway, October 20, 2015. Two consignments of crop seeds will be deposited next year in a “doomsday vault” built in an Arctic mountainside to safeguard global supplies. The vault, which opened on the Svalbard archipelago in 2008, is designed to protect crop seeds, such as beans, rice and wheat against the worst cataclysms of nuclear war or disease. (Photo by Anna Filipova/Reuters)

Assassin’s Creed is a game that is set in the past with the main character’s subconsciousness traveling through the fabric of time to acquire hidden knowledge. The level designers of Assassin’s Creed Unity have meticulously recreated the streets of 1789 Paris to allow the users to become completely engulfed by the atmosphere of this proud and ancient city. Each year, games are becoming more and more realistic, and soon the line between movie footage and computer generated world will completely blur. This is both scary and exciting prospect, yet there is no doubt that someday, virtual world will be indistinguishable from the real one. To illustrate this, Damien Hypolite has taken a series of photos which compare scenes from Assassin’s Creed to the real placed in modern Paris. (Photo by Damien)

MS Allure of the Seas is an Oasis-class cruise ship owned and operated by Royal Caribbean International. The Oasis class are the largest passenger ships ever constructed, and Allure is 50 millimetres (2.0 in) longer than her sister ship Oasis of the Seas, though both were built to the same specifications. Designed under the name “Project Genesis”, she was ordered from Aker Finnyards in February 2006 and her construction began at the Perno shipyard, Turku, Finland, in February 2008. She was named in May 2008 after a contest was held to name her and her sister. The keel of Allure of the Seas was laid on 2 December 2008, shortly after the shipyard had been acquired by STX Europe.