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)

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.

Coonoor is a municipality in the Nilgiris district in the state of Tamil Nadu, India. It is known for its production of Nilgiri tea. Coonoor is located at an altitude of 1,850 m above sea level and is the second largest hill station in the Nilgiri hills after Ooty. Coonoor is known for the massive private tea plantations that surround the hills. The local economy of Coonoor runs on tourism and tea production. (Photo by Qamar Abbas)

A production department of a textile factory is seen abandoned in Kaduna, Nigeria November 3, 2016. President Muhammadu Buhari hopes to revive the once flourishing textile and leather industries in northern Nigeria to end the country's dependence on oil exports and diversify Africa's biggest economy. (Photo by Afolabi Sotunde/Reuters)

Residents of the Huachipa populous district, east of Lima, are helped on March 17, 2017, by police and firemen rescue teams to cross over flash floods hitting their neighbourhood and isolating its residents. The climatic phenomenon El Niño is causing muddy rivers overflows on the entire Peruvian coast, isolating hundreds of people, mostly residents of Lima's industrial belt neighbourhoods. (Photo by Cris Bouroncle/AFP Photo)

Models sit backstage during an outdoor show at Dakar Fashion week on December 12, 2020 just outside Dakar, Senegal. With Senegal's low incidence of Covid-19, Dakar's marquee fashion event looked markedly more normal than its counterparts in other global capitals, whose fashion weeks were heavily curtailed or canceled. (Photo by Finbarr O'Reilly/Getty Images)

Vogue dancer Xiong Daiki, 22, takes a video of his team to promote vogue dancing, almost a year after the global outbreak of the coronavirus disease (COVID-19) in Wuhan, Hubei province, China on December 15, 2020. During lockdown, Daiki, his students and friends practiced at home in their bedrooms, staying in touch by sharing videos of new dance routines. (Photo by Aly Song/Reuters)

A celebrant takes part in the ninth Hong Kong Buddha Sunning Festival at the Tai Mo Shan lookout on February 18, 2020 in Hong Kong, China. The global death toll from the coronavirus epidemic rose above 200, with all but five of those and the vast majority of the more-than 75,000 cases occurring on mainland China. (Photo by Billy H.C. Kwok/Getty Images)