Pulp Fiction was a popular (and extremely violent) movie which depicted exactly what you're describing. John Travolta is comfortable with his heroin guy - they

Pulp Fiction was a popular (and extremely violent) movie which depicted exactly what you're describing. John Travolta is comfortable with his heroin guy - they banter, talk about travel, and then discuss the dope in genial terms. When money changes hands, it's practically a formality between two people who are acting out a ritual, like a regular at a coffee shop. I guess it doesn't end up too well for Travolta, but I think his dealer made it out okay. Come to think of it, that guy had a negative body count by the end of the film; he saved Uma Thurman's life.