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.

Mud Madness at the annual Jaffa Cakes charity three-mile run at Foymore Lodge near Portadown this afternoon, on April 13, 2014. A total of a thousand competitors and fun-runners took part in the two races held over the mudstrewn endurance course. (Photo by Alan Lewis/Photopress Belfast)

The Acura Stage area is flooded after a storm dumped several inches of rain on the second Saturday of the New Orleans Jazz Fest at the Fair Grounds, Saturday, April 30, 2016. (Photo by David Grunfeld/NOLA.com/The Times-Picayune via AP Photo)

Flames from the Falls Fire burn on a hillside along South Main Divide Road in the Cleveland National Forest as firefighters drive through the area on Monday, August 5, 2013. (Photo by Kurt Miller/AP Photo/The Press-Enterprise)

A devotee participates in Holi celebrations at the Nandagram temple, on March 22, 2013. (Photo by Manish Swarup/Associated Press)

A Taliban fighter jumps into the vehicle after praying at Deh Bori square in Kabul, Afghanistan on October 18, 2021. (Photo by Zohra Bensemra/Reuters)

In this Sunday, February 18, 2018 photo, Palestinian camel herder Salem Rashaideh, leads the way for the camels in the territory of Israeli Kibbutz Kalya, near the Dead Sea in the West Bank. For three months a year, in the winter time Bedouin Arab herders take their 130 camels to graze on the shores of the Dead Sea, at the lowest place on Earth. (Phoro by Oded Balilty/AP Photo)

An ice swimming enthusiast dressed as Neptune takes to the frigid waters of Orankesee lake during the 27th annual "Winter Swimming in Berlin" on January 8, 2011 in Berlin, Germany. A local swimmers' group called the “Berlin Seals” invite ice swimmers from across Germany and abroad to the annual event. Members claim ice swimming is good for the body's blood circulation. (Photo by Sean Gallup)