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.

A instructor (2nd L) from the Philippine Mermaid Swimming Academy assists participants of a monofin swimming summer workshop as they practise floating in the water of a private pool in Paranaque city, metro Manila April 5, 2014. The Philippine Mermaid Swimming Academy workshops, which were originally conducted on the beaches of Boracay Island, central Philippines, currently cost 1,800 pesos per person ($40) for a two-hour session. (Photo by Romeo Ranoco/Reuters)

A tour group wanders through block 7 of Eastern State Penitentiary in Philadelphia, Pennsylvania April 30, 2014. Opened in 1829, with the original corrective system of “confinement in solitude with labor”, the penitentiary housed about 75,000 inmates in its 142 years of operation. At Eastern State reunions, former inmates, staff and guard gather to share memories and trade stories and get a chance to describe their experiences in question-and-answer sessions with the public. (Photo by Mark Makela/Reuters)

“The Wii U is an upcoming home video game console by Nintendo, and the direct successor to the Wii. The system is expected to be released in 2012 and was unveiled during Nintendo's press conference at the Electronic Entertainment Expo 2011 on June 7, 2011. The Wii U is the first Nintendo console to produce 1080p high-definition graphics, and features a new controller with an embedded touchscreen. The controller allows a player to continue a gaming session by displaying the game even when the television is off. The system will be fully backwards compatible with Wii, and Wii U games can support compatibility with Wii peripherals, such as the Wii Remote and Wii Balance Board”. – Wikipedia

Photo: The new Nintendo game console Wii U is displayed at the Nintendo booth during the Electronic Entertainment Expo on June 7, 2011 in Los Angeles, California. The Wii U will have HD graphics, a controller with a 6.2 inch touchscreen and be compatible with all other Wii accessories. (Photo by Kevork Djansezian/Getty Images)

Athlets run during the women's 3000 meter steeplechase at the International Athletics Meeting in Lucerne, Switzerland, 14 June 2016. (Photo by Alexandra Wey/EPA)

A competition, now in its 43rd year, dedicated to showcasing the beautiful and bizarre as seen under a light microscope attracted over 2,000 entries from 88 countries. Here: Honorable Mention by Emre Can Alagöz, Istanbul, Turkey: The eyes of a jumping spider, magnified 6x. (Photo by Emre Can Alagöz/2017 Nikon Small World Photomicrography Competition)