Before Christopher Nolan’s critically acclaimed The Dark Knight (2008) even came out, audiences knew the film’s most famous line. A viral marketing campaign infected cities around the world, with posters of the Joker’s silhouette and ragged, red smile appearing across bus-stops and billboards. At the centre of the campaign was the film’s tagline – “Why so serious?” There was even a whysoserious.com website made that gave hints about the Joker launched a year before the film came out.
The line is first uttered by the Joker (Heath Ledger, in an Oscar-winning performance) when he begins taking over Gotham’s underworld by springing from a body bag and sticking a switchblade in the gangster Gambol’s (Michael Jai White) mouth. The Joker then menacingly recounts how his father scarred his own mouth, key to which is his father’s question, "Why so serious?", in a scene that ratchets up the tension each time the phrase is used. When the Joker reaches the end of his story the stress is excruciating as it becomes obvious, to the audience and the character, that Gambol’s about to earn his own slashed smile. The Joker pauses and peers at one of Gambol's lackeys, whose face is a mask of terror, causing the Joker to curiously ask, ‘Why so serious?’ before pulling the blade with a flourish.
The moment is a mixture of horror and ironic humour. Of course, the lackey wears a grim expression – his boss is being threatened by one of cinema’s most memorable villains. And that line has become one of the most memorable in cinema.
Not only did the film make over $1 billion USD at the box-office, but it was also a critical hit, earning eight Oscar nominations and winning two. For his chilling performance as the Joker, Heath Ledger won the second posthumous Best Supporting Actor award. As the film’s popularity grew, so did internet searches for the phrase "Why so serious?".
As KnowYourMeme.com reports, "In July of 2008, searches for Why So Serious spiked not only in the US, but also across the globe in places like Singapore, Hong Kong, Mexico, Taiwan, Malaysia and Sweden." The line was quickly adopted by meme makers, who applied the Joker style make-up and phrase to countless pictures on the Internet (and of course, cats), which were sent to other users who were being unnecessarily angry or emotional.
In addition, the phrase was remixed into songs that relied solely on the phrase for lyrics, while it also appeared on official merchandise for the films, including T-shirts, posters and coffee cups. Users on the influential YouTube channel MovieClips have played the scene over 3.35m times, IGN.com ranked the line #95 on their Top Movie Moments and it has been widely adopted by people online and in real life, who instinctively understand the line’s menace and use it to pay homage to a great performance or use it ironically for new, humorous purposes.