Kenyan women protest for the right to wear whichever clothes they want, at a demonstration in downtown Nairobi, Kenya Monday, November 17, 2014. A recent incident in which a mob of men surrounded a woman and tore her clothes off, leaving her naked on the street in front of a bus stop after alleging that she was improperly dressed, is one of several such videos that have surfaced online in recent days leading to a groundswell of anger that on Monday prompted around 1000 demonstrators, including a number of men supporting the women's cause, to march through the capital and protest online using the hashtag #MyDressMyChoice. (Photo by Ben Curtis/AP Photo)

This picture taken on January 25, 2015 shows a participant taking part in an ice water challenge in Zhangjiajie, central China's Hunan province. Participants were required to stay in an ice pond, holding an ice block while eating ice-cream with an electric fan blowing at them. (Photo by AFP Photo/Stringer)

A man wears a sweater covered in Irish themed pins as he stands with thousands of spectators to watch the 254th New York City St. Patrick's Day parade up 5th Avenue in the Manhattan Borough of New York, March 17, 2015. (Photo by Mike Segar/Reuters)

Devotees push the chariot of Rato Machhindranath during the chariot festival at Bungamati in Lalitpur April 22, 2015. Rato Machhindranath is known as the god of rain and both Hindus and Buddhists worship Machhindranath for good rain to prevent drought during the rice harvest season. (Photo by Navesh Chitrakar/Reuters)

Libyan forces allied with the U.N.-backed government fire weapons during a battle with IS fighters in Sirte, Libya, July 21, 2016. (Photo by Goran Tomasevic/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.

A student shouts slogans against Venezuelan President Nicola Maduro during a protest on the main highway in Caracas on March 30, 2017. Venezuela' s Supreme Court took over legislative powers Wednesday from the opposition- majority National Assembly, whose speaker accused leftist President Nicolas Maduro of staging a “coup”. (Photo by Juan Barreto/AFP Photo)

Mosha, the elephant that was injured by a landmine, has her prosthetic leg attached at the Friends of the Asian Elephant Foundation in Lampang, Thailand, June 29, 2016. Mosha was 7 months old when she stepped on a land mine near Thailand’s border with Myanmar and lost a front leg. That was a decade ago... (Photo by Athit Perawongmetha/Reuters)