A villager stretches as the Mayon volcano spews ashes and lava in Legaspi city, Albay province, Philippines, 12 June 2023. The restive Mayon volcano has begun spewing lava and small eruptions, putting the lives of thousands of people at risk from possible violent explosion. (Photo by Francis R. Malasig/EPA/EFE)

Annabelle, 13, and her sister Estelle, 10, both artistic gymnasts from Borna, hang from the rings during their training, ahead of the Special Olympics World Games Berlin 2023, the world's largest sports movement for people with intellectual disabilities, at the Federal base for competitive gymnastic artistics in Chemnitz, Germany on May 6, 2023. (Photo by Annegret Hilse/Reuters)

US Maia Weintraub (L) and Japan's Sera Azuma compete during the Women's Team Foil event Bronze medal match, as part of the FIE Fencing World Championships at the Fair Allianz MI.CO (Milano Convegni) in Milan, on July 29, 2023. (Photo by Andreas Solaro/AFP Photo)

A worker stands next to a Southern Two-toed Sloth at the Sloth and Friends Studio inside Hong Kong Ocean Park on August 3, 2023 in Hong Kong, China. (Photo by Vernon Yuen/Rex Features/Shutterstock)

A SpaceX Falcon 9 rocket lifts off in Florida on Saturday, October 21, 2023. The rocket is carrying 23 Starlink satellites. (Photo by Malcolm Denemark/AP Photo)

A person dressed as a zombie mermaid poses for a photo as she interacts with patrons at the Haunted Hotel Takeover Halloween party at hotel Ziggy in West Hollywood, California, U.S., October 29, 2022. (Photo by Mario Anzuoni/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.

Kenyan women protest for the right to wear whichever clothes they want, at a demonstration in downtown Nairobi, Kenya Monday, November 17, 2014. A recent incident in which a mob of men surrounded a woman and tore her clothes off, leaving her naked on the street in front of a bus stop after alleging that she was improperly dressed, is one of several such videos that have surfaced online in recent days leading to a groundswell of anger that on Monday prompted around 1000 demonstrators, including a number of men supporting the women's cause, to march through the capital and protest online using the hashtag #MyDressMyChoice. (Photo by Ben Curtis/AP Photo)