A sloth peeks out from behind a door on a floating house in the “Lago do Janauari” near Manaus, Brazil, Tuesday, May 20, 2014. Manaus is one of the host cities for the 2014 World Cup in Brazil. (Photo by Felipe Dana/AP Photo)

Brazil's Kathellen in action with Australia's Alanna Kennedy during the Australia vs Brazil, Group C match at the FIFA Women's World Cup at Stade La Mosson Stadium on June 13th 2019 in Montpellier, France. (Photo by Eric Gaillard/Reuters)

#14 Kathellen of Brazil show her dejection after the 2019 FIFA Women's World Cup France Round Of 16 match between France and Brazil at Stade Oceane on June 23, 2019 in Le Havre, France. (Photo by Yves Herman/Reuters)

An indigenous woman looks on during the Terra Livre (Free Land) camp, a protest-camp to defend indigenous land and cultural rights that they say are threatened by the right-wing government of Brazil's President Jair Bolsonaro, in Brasilia, Brazil on April 4, 2022. (Photo by Adriano Machado/Reuters)

Central Bangkok and the Chao Phraya River are seen from an abandoned skyscraper in Bangkok April 19, 2015. The abandoned building, known as Satorn Unique, dubbed the “ghost tower” was destined to become one of Bangkok's most luxurious residential addresses but construction was never completed as the Thai economy was hit during the 1997 Asian Financial Crisis. Now, many travellers visit and explore 49-storey skyscraper. (Photo by Athit Perawongmetha/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.

In this October 6, 2018, photo, a craftsman makes daggers or “Jambiyya” in Yemeni Arabic, made out of remains of missiles, at his workshop, in Hajjah, Yemen. Missiles raining on Yemen from the jets of the Saudi-led coalition fighting Houthi rebels are killing thousands of civilians and militiamen alike, but amid crashing economy, some Yemenis see the bright side of it: they make daggers out of the fragments of the missiles for ordinary men traditionally wear for prestige and a show of courage. (Photo by Hammadi Issa/AP Photo)