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.

Indian commuters travel in a local train in Kolkata, India, Tuesday, February 26, 2013. Indian Railway Minister Pawan Kumar Bansal is presenting the country's rail budget for next fiscal year in the parliament Tuesday, Feb. 26, 2013. Indian railway network is one of the world's largest, with some 14 million passengers daily and some 64,000 kilometers (40,000 miles) of railway track cut through some of the most densely populated cities. (Photo by Bikas Das/AP Photo)

“Sky burial or ritual dissection was once a common funerary practice in Tibet wherein a human corpse is cut in specific locations and placed on a mountaintop, exposing it to the elements or the mahabhuta and animals – especially to birds of prey. The location of the sky burial preparation and place of execution are understood in the Vajrayana traditions as charnel grounds. In Tibet the practice is known as jhator, which literally means, «giving alms to the birds»”. – Wikipedia

Photo: A burial master chops bones of a body to feed vultures during a celestial burial ceremony on April 19, 2006 in Dari County of Guoluo Prefecture, Qinghai Province, northwest China. Celestial burial is a traditional funeral of Tibetan people, which began in the 7th century. (Photo by China Photos/Getty Images)

A little girl hangs three Siamese kittens on a washing line in a garden in Croydon, London. (Photo by Fox Photos/Getty Images). 14th July 1931

Policemen look at a wax figure of Rowan Atkinson, dressed as his popular television character Mr. Bean, on display outside a wax figure museum in Guangzhou, Guangdong province, August 24, 2014. (Photo by Alex Lee/Reuters)

Indian dancers perform a fire breathing act during a procession to mark the 661st anniversary of the birth of Hindu guru Bawa Lal Dayal Maharaj in Amritsar on February 9, 2016. Bawa Lal Dayal Maharaj, a popular leader of his time, is especially revered by devotees of a temple in the town of Dhyanpur, some 45 kms north of Amritsar. (Photo by Narinder Nanu/AFP Photo)

Body builders preparing at the backstage during the Bodybuilding Cup in Kiev, Ukraine on November 7, 2015 which includes classic bodybuilding, physicist and body fitness and bikini in the competition. (Photo by Nazar Furyk/Pacific Press)

A mother prays for success for her child in the college entrance examinations at a Buddhist temple in Seoul, South Korea, November 12, 2015. About 630,000 students on Thursday sat for the annual exams that could lead them to one of the country's top universities. In South Korea, there is no higher achievement than to be accepted by a prestigious university. As a result, many students prepare for these entrance exams from an early age, often studying up to 16 hours a day for years to take this test. (Photo by Kim Hong-Ji/Reuters)