Attendees Rosalia Rohwer and Jennifer Salenger dress up as characters from the game “Just Dance” at E3, the world's largest video game industry convention in Los Angeles, California on June 12, 2018. (Photo by Mike Blake/Reuters)

Heidi Klum, dressed as a werewolf, performs a dance from Michael Jackson's "Thriller" video her 18th Annual Halloween Party at Moxy Times Square on Tuesday, October 31, 2017, in New York. (Photo by Evan Agostini/Invision/AP Photo)

A column of sand and front of clouds are seen by dash cam as the car drives near a tornado in Dragalina, Calarasi county, Romania April 30, 2019 in this still image taken from a video obtained from social media. (Photo by Alexandra Puscasu via Reuters)

Russian President Vladimir Putin speaks via video call during a news conference in Moscow, Russia, Thursday, December 17, 2020. This year, Putin attended his annual news conference online due to the coronavirus pandemic. (Photo by Alexander Zemlianichenko/AP Photo)

American singer and songwriter Kacey Musgraves performs onstage during the 2021 MTV Video Music Awards at Barclays Center on September 12, 2021 in the Brooklyn borough of New York City. (Photo by John Shearer/MTV VMAs 2021/Getty Images for MTV/ViacomCBS)

Girls of the Long Horn Miao ethnic minority group wear headdresses as they prepare gather for Tiaohua or Flower Festival as part of the Lunar New Year on February 6, 2017 in Longga village, Guizhou province, southern China. (Photo by Kevin Frayer/Getty Images)

Long-tailed mayflies (Palingenia longicauda) at Tisza river near Tiszainoka 135km (84 miles) southeast of Budapest, June 23, 2013. Millions of these short-lived mayflies engage in a frantic rush to mate and reproduce before they perish in just a few hours during “Tiszaviragzas” or Tisza blooming season from late spring to early summer every year. (Photo by Laszlo Balogh/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.