In Korea, bowing expresses greeting or gratitude. But when combined with extreme machismo, it becomes a fear response. A normal bow is 30-40 degrees; the extreme macho bow is a full 90 degrees—faster, with a louder greeting. This bowing style is common among gangsters and military personnel, but also in college clubs and among K-pop idols.
Hello 90 is an interactive video installation where people on screen bow at 90 degrees when you enter.

