Few of us have ever (knowingly) met a hitman, and yet they're so ubiquitous in popular culture that a Martian researching earthling lifestyles might reasonably assume it was a viable career choice, on a par with policeman or teacher. But I'm guessing real life hitmen are nothing like their counterparts on screen, who are as much symbols, or triggers to set the plot in motion, as credible characters. They're a close cousin to the western gunslinger (as played by Gregory Peck in The Gunfighter or Henry Fonda in Once Upon a Time in the West), killers who thrive in a lawless environment, who have no real place in civilised society, but whose introduction into the story ups the stakes to life or death.