Hair on fire is an idiomatic expression used to represent a state of being really busy or overwhelmed with something.
It can also be used, as a state of being really passionate about things to the point of acting a bit more “wild” or “erratic”.
For an example : I wish this party was a bit energetic. This one isn’t setting my hair on fire at all.
The term is believed to be originated from Navy aviators, who used the phrase in hair-rising urgent situations in the military, which can be traced back to the 1970s and 1980s.
Even before the Navy aviators picked up the phrase and made it common, it could be found in ancient teachings of Buddhists who said, a person should seek enlightenment as eager as someone whose hair is on fire would seek water.
Later, in 1939 Irish novelist James Joyce used the term in his novel Finnegan’s Wake.
How it got placed from the military to the civilian populous as slang is thanks to the top-hit movie Top Gun in 1986, where the phrase “You’re not going to be happy unless you’re going Mach 2 with your hair on fire.” was used.
The has become rapidly widespread since 2000 and not just in the media and in social media sites but as marketing strategy.
In 2007 a book was published with the title Teach Like Your Hair’s on Fire: The Methods and Madness Inside Room 56.