Most people know it, it is a well known line from the cult classic Fright Night (1985).
As a non-native English speaker, I can't understand what makes this particular line so relevant and/or important. It seems to be perhaps the most remembered and quoted line from that movie (even the documentary about the movie is called You're So Cool, Brewster! The Story of Fright Night (2016)), but within the context of the movie and the plot development it has very little (if not zero) relevance.
Am I missing something? Is this something more related to the English language than the movie itself? Why did it gain so much relevance?