Competitors take part in the International Medieval Combat Federation World Championships at Scone Palace on May 10, 2018 in Perth, Scotland. Thousands of visitors are expected to attend the crowning place of Scottish Kings, Scone Palace for the IMCF World Championships which has five hundred competitors and officials from all over the world, from the UK to as far afield as Australia, South Africa and Mexico. (Photo by Jeff J. Mitchell/Getty Images)

Festivalgoers dance during the Balaton Sound music festival in Zamardi, Hungary, July 5, 2018. Balaton Sound is one of Europe's largest open air electronic music festivals. Held annually since 2007 on the southern bank of Lake Balaton, Hungary, it features live acts and DJ's from all around the world, from established artists to new names. The event was co-created by the organizers of Sziget Festival. (Photo by Bernadett Szabo/Reuters)

Mikhail Baburin, 66, talks to his cat Marquis at his house in the remote Siberian village of Mikhailovka, Krasnoyarsk region, Russia, December 5, 2016. Baburin, a former Navy man, barge worker and employee of a military plant in Krasnoyarsk, is the last inhabitant of Mikhailovka, which was founded in the 19th century by migrants from Russia's Mordovia region. He moved in 2000 to Mikhailovka where he was born and has lived there all alone for the last 10 years with only domestic animals. (Photo by Ilya Naymushin/Reuters)

Armin Senoner conceptualizes class system based semiotic alpine escape all visuals courtesy of armin senoner. From birth, every human is organized through the hierarchical class system. Without regard to personal characteristics in the least, each is donned with a label; lower, middle, or upper. Society at large is innately regulated because by it, the rich do anything to remain at the top, the middle tries to overthrow the rich, and the poor just try to survive. Modern times, though less brutal, is no less restrained by the unspoken rules of social division.

Tracy Sarita celebrates the sunrise during the Burning Man 2015 “Carnival of Mirrors” arts and music festival in the Black Rock Desert of Nevada, September 3, 2015. Approximately 70,000 people from all over the world are gathering at the sold-out festival to spend a week in the remote desert to experience art, music and the unique community that develops. (Photo by Jim Urquhart/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.

A tattoo artist applying ink on a girl' s arm during the 2017 Moscow Tattoo Festival at Moscow' s Amber Plaza Shopping Center in Moscow, Russia on April 1, 2017. Tattoo artists from all over the world take part in the event. The festival' s program includes a tattoo contest, body taping art marathon, masterclasses, round table discussions and conferences. (Photo by Valery Sharifulin/TASS)