A caterpillar driven ferry with a 24 horsepower engine takes holidaymakers from the mainland at Bigbury in Devon to Burgh Island, a quarter of a mile away. (Photo by Reg Speller/Fox Photos/Getty Images). 4th April 1935

Kendall Jenner attends “Rei Kawakubo/Comme des Garcons: Art Of The In-Between” Costume Institute Gala – Arrivals at Metropolitan Museum of Art on May 1, 2017 in New York City. (Photo by David Fisher/Rex Features/Shutterstock)

Jared Leto, holding a model of his own head, attends The Metropolitan Museum of Art's Costume Institute benefit gala celebrating the opening of the “Camp: Notes on Fashion” exhibition on Monday, May 6, 2019, in New York. (Photo by Charles Sykes/Invision/AP Photo)

(L-R) Kendall Jenner, Kim Kardashian, and Kylie Jenner attend The 2023 Met Gala Celebrating “Karl Lagerfeld: A Line Of Beauty” at The Metropolitan Museum of Art on May 01, 2023 in New York City. (Photo by Kevin Mazur/MG23/Getty Images for The Met Museum/Vogue)

Just a week before Rio de Janeiro hosts South America's first Olympics, city residents expressed mixed feelings about the cost and security of the Games, while holding out hope they will bring joy to a nation facing economic and political crises. The conflicted thoughts mirror a recent survey by the Datafolha polling group showing that half of Brazilians were opposed to holding the Games, while 63 percent think the costs of hosting the event will outweigh benefits. (Photo by Pilar Olivares/Reuters)

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.

Russian soldiers write home while serving on the Eastern Front during World War I, circa 1915. (Photo by Hulton Archive/Getty Images)

Egyptian bootblacks cleaning a European's shoes in Cairo. (Photo by Hulton Archive/Getty Images). Circa 1870