Several beaches along South Florida's Atlantic coast line were closed after thousands of sharks were seen migrating in the waters. The sharks were migrating from Boca Raton to Jupiter since the beginning of March, marine biologists told NBC Miami. Photo: A spinner shark swims just offshore on Midtown Beach in Palm Beach on Tuesday. (Photo by Jeffrey Langlois/Palm Beach Daily News)

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.

People protest for greater action against climate change during the People's Climate March on September 21, 2014 in New York City. The march, which calls for drastic political and economic changes to slow global warming, has been organized by a coalition of unions, activists, politicians and scientists. (Photo by Andrew Burton/Getty Images)

People hold an umbrella under strong wind on the promenade of Victoria Habour as tropical cyclone Ma-on approaches Hong Kong, Wednesday, August 24, 2022.Tropical Storm Ma-on was gaining strength as it headed for Hong Kong and other parts of southeastern China on Wednesday after displacing thousands in the Philippines. (Photo by Anthony Kwan/AP Photo)

Bride Ana Vallejos, wearing a traditional “Caporales” Andean outfit, is escorted by her parents to her wedding celebration, in La Paz, Bolivia, Saturday, December 12, 2020. As a measure to reactivate the economy, the Bolivian government lifted restrictions to help curve the spread of the new coronavirus. Sporting, religious and cultural events may take place publicly until mid-January. (Photo by Juan Karita/AP Photo)

A three minute time exposure shows the launch of a SpaceX Falcon 9 from Cape Canaveral Space Force Station Launch Complex 40, Thursday, January 7, 2021 in Port Canaveral, Fla. The rocket is carrying the Turksat 5A satellite for Turkey. (Photo by Malcolm Denenark/Florida Today via AP Photo)

Women dance on top of a car as revelers enjoy spring break festivities despite an 8pm curfew imposed by local authorities, amid the coronavirus disease (COVID-19) pandemic, in Miami Beach, Florida, U.S., March 20, 2021. (Photo by Marco Bello/Reuters)

An injured Palestinian demonstrator is helped during a protest against the planned evictions of Palestinian families in the Sheikh Jarrah neighborhood of east Jerusalem, Saturday, May 8, 2021. (Photo by Oded Balilty/AP Photo)