Like many big city dwellers, Berliners have a reputation for being aloof, outspoken and blunt. Originating in a need for order, this way of functioning is cheekily called the Berliner Schnauze, literally the Berliner Snout, and operates on the assumption that others are doing things the wrong way which needs immediate correction.
Victims of the Berliner Schnauze are usually oblivious passersby who are told off for something they didn't realise they were doing wrong such as people who are in too much of a rush to get into the U-Bahn before other passengers can come out or neighbours who do a sloppy job with their recycling. Whatever may be the case, the Berliner Schnauze strikes without warning, delivering a brutal level of honesty that was never asked for.
On paper, Berliner Schnauze is simply a dialect of German spoken around Berlin but in reality, it is an emotional dialect with working-class attitude and influences from French and Yiddish. Locals think of it as a quick-witted linguistic game that acts as the colloquial language of Berlin. It is a big part of multicultural Berlin's character as a city. For most born and bred Berliners, it is a way of life.
Source: BBC Culture