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.

Hundreds of hardy swimmers across Britain braved jumping into freezing cold waters for a annual Christmas Day dip on December 25, 2017. (Photo by Dave Nelson/The Sun)

A tourist clad in Japanese kimono takes a picture in front of s portrait shop in Tokyo's Asakusa district, Thursday, February 15, 2018. Asakusa is a popular district four tourists in the capital. (Photo by Shizuo Kambayashi/AP Photo)

Emma Sees, Valor Christian, #6, accidentally grabs Windsor's Alexa Kopren's hair while both were chasing after the ball in the second half of the Colorado State girls 4A soccer championship at Dick's Sporting Goods Park May 23, 2018. (Photo by Andy Cross/The Denver Post)

American model and television personality Kendall Jenner attends the Longchamp 70th Anniversary Celebration at Opera Garnier on September 11, 2018 in Paris, France. (Photo by Dominique Maitre/WWD/Rex Features/Shutterstock)

Barber Herman Mulyana (R) gives a haircut to a customer while wearing protective attire made from plastic garbage bags at a barbershop in Bogor, Indonesia, 06 April 2020. The Trade Ministry of Indonesia issued a regulation temporarily recinding all requirements for the import of protective gear and medical equipment, to counter shortages of many items used to treat COVID-19 patients and prevent the further spread of the disease. (Photo by Adi Weda/EPA/EFE)

In a photo taken on April 2, 2020 a staff member feeds a raccoon at the Table A Raccoon Cafe in Seoul. Business has been devastated by the coronavirus outbreak, with South Koreans staying at home under social distancing guidelines, and tourism disappearing. But unlike other firms, animal cafes have to stay open so that staff can look after their stock. (Photo by Ed Jones/AFP Photo)