A policeman aims his weapon in Istanbul, Turkey July 16, 2016. Members of Turkey's armed forces said they had taken control of the country Friday as explosions, gunfire and a reported air battle between loyalist forces and coup supporters erupted in the capital. President Erdogan remained defiant and called on people to take to the streets to show support for his embattled government. (Photo by Kemal Aslan/Reuters)

Guests spend the night in the beach bar so called club of the visionairs in the early morning hours of August 21, 2011 in Berlin, Germany. Berlin, which is among Europe's most popular travel destinations, is crisscrossed with canals and rivers over which lead a total of 564 bridges. The city's ample access to water has encouraged many bar and restaurant owners to create beach atmosphere as a growing summer day- and nightlife institution. (Photo by Carsten Koall/Getty Images)

An adult helps a young girl light a cigarette as a band plays in the background in the village of Vale de Salgueiro, northern Portugal, during the local Kings' Feast Friday, January 5, 2018. The village's Epiphany celebrations, called Kings' Feast, feature a tradition that each year causes an outcry among outsiders: parents encourage their children, some as young as 5, to smoke cigarettes. (Photo by Armando Franca/AP Photo)

Police officers detain a woman during an opposition rally to protest the official presidential election results in Minsk, Belarus, Saturday, September 19, 2020. Daily protests calling for the authoritarian president's resignation are now in their second month and opposition determination appears strong despite the detention of protest leaders. (Photo by TUT.by via AP Photo)

Somalis remove the body of a man killed in a blast in the capital Mogadishu, Somalia Saturday, October 14, 2017. A huge explosion from a truck bomb has killed at least 20 people in Somalia's capital, police said Saturday, as shaken residents called it the most powerful blast they'd heard in years. (Photo by Farah Abdi Warsameh/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.

This picture taken on October 18, 2018 shows a “trolley boy” pushing a home- made cart along a train track in Manila, Philippines. Scores of commuters in the city of about 12 million are propelled to their destinations daily by so-called “trolley boys” pushing metal carts that ply a few segments of the sprawling capital's railroads. (Photo by Noel Celis/AFP Photo)