People are reflected on a soap bubble lying on a road during the evening in New Delhi, India, June 23, 2015. (Photo by Anindito Mukherjee/Reuters)

Who Left The Tap Running by artist Simon McGrath is seen as part of the Sculpture by the Sea outdoor exhibition along the Bondi to Bronte coastal walk on November 4, 2011 in Sydney, Australia. (Photo by Lisa Maree Williams/Getty Images)

An Egyptian street vendor carries plastic dishes on a street decorated for the holy month of Ramadan in old Cairo, Egypt June 1, 2016. (Photo by Amr Abdallah Dalsh/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.

(L-R) Jesse Montana , Kyle Chan, James Kennedy and Anthony F. attend Kyle Chan's “Star Wars vs. s*xy Aliens” Birthday Party at Sofitel Hotel on February 19, 2019 in Los Angeles, California. (Photo by Robin L Marshall/Getty Images)

Abbas (1944 – 25 April 2018) was an Iranian photographer known for his photojournalism in Biafra, Vietnam and South Africa in the 1970s, and for his extensive essays on religions in later years. He was a member of Sipa from 1971 to 1973, a member of Gamma from 1974 to 1980, and joined Magnum Photos in 1981. Here: Kuwait, 1991. (Photo by Abbas Attar/Magnum Photos)

Children surround a man, left, that fell down while walking on a street suspected of having contracted the Ebola virus in the city of Monrovia, Liberia, Tuesday, August 19, 2014. The World Health Organization says the outbreak has killed more than 1,200 people, while authorities struggle to contain its spread and treat the sick. (Photo by Abbas Dulleh/AP Photo)

Elizabeth Nicolaou, a final year student with the Royal Academy of Dance, strikes a pose on April 28, 2022 near the Cutty Sark ship in Greenwich, London ahead of International Dance Day. First celebrated in 1982, International Dance Day has taken place every year since in anniversary celebration of the birth of Jean-Georges Noverre (1727-1810), considered the creator of modern ballet. (Photo by Guy Corbishley/Alamy Live News)