Lucaz Adamus (3), from Lucan, enjoying the Dublin Racing Festival, at Leopardstown Racecourse in Dublin, Ireland on February 5, 2023. (Photo by Tom Maher/Inpho)

A Filipino activist builds an effigy depicting Philippine President Ferdinand Marcos Jr. ahead of Marcos' first State of the Nation Address, in Quezon City, Metro Manila, Philippines on July 24, 2022. (Photo by Lisa Marie David/Reuters)

A member of the Boi Bumba Garantido association performs during the Boi Bumba folklore festival at the Bumbodromo in Parintins, Amazonas State, Brazil, on June 28, 2024. Parintins is well-known internationally for its Boi Bumba folklore festival, which lasts for three days in late June and whose themes, costumes, and songs are based on indigenous cultures of the Amazon rainforest. (Photo by Michael Dantas/AFP Photo)

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.

A mine detection rat is given banana as a reward after successfully identifying an inactive mine on July 2, 2015 in Siem Reap, Cambodia. The Cambodian Mine Action Center (CMAC) working with the Belgian NGO APOPO has recently begun testing the feasability of using large mine detection rats from Tanzania to help clear fields of mines and unexploded ordnance in one of the most bombed and mined countries in the world. (Photo by Taylor Weidman/Getty Images)

People carry bags containing their belongings past a burning residential block, caused by a recent shelling according to locals, on the outskirts of Donetsk, eastern Ukraine February 9, 2015. (Photo by Maxim Shemetov/Reuters)

Visitors watch as Grigory Broverman, a member of the Cryophile winter swimmers club, pours a bucket of cold water over his 6-year-old daughter Liza during a flash mob, part of a celebration of Polar Bear Day at the Royev Ruchey Zoo in a suburb of the Siberian city of Krasnoyarsk, Russia, November 29, 2015. The air temperature was around minus 5 degrees Celsius. (Photo by Ilya Naymushin/Reuters)

Cemetery workers lift a corpse from a coffin to a metal plate as they prepare the body for cremation at a cemetery in Maracaibo, Venezuela, November 27, 2019. Some overcome the financial burden of a relative's death by renting caskets, a cheaper option than buying one. (Photo by Rodrigo Abd/AP Photo)