A movie doesn't have to be successful to be a classic. Take "Heathers" -- written by Daniel Waters, directed by Michael Lehmann, starring Winona Ryder.
Ryder, fresh off "Beetlejuice," played another death-obsessed teenager. Unlike gothic outsider Lydia Deetz, though, Veronica Sawyer from "Heathers" is in the in-crowd. She hangs out with Westerburg High School's trio of mean girls, all named Heather, but feels disillusioned. So her new bad boy lover J.D. (Christian Slater) convinces her to pull a lethal prank on queen bee Heather Chandler (Kim Walker).
"Heathers" is the template for other biting black comedy teen movies, from "Mean Girls" to "Jennifer's Body." It even inspired a "Heathers" musical! But it only made $1.1 million on a $3 million budget.
Entertainment Weekly's oral history of "Heathers" (published in 2014 for its 25th anniversary) has some explanations for why it flopped. Distributor New World Pictures was going bankrupt at the time (it would be swallowed up by News Corp in 1997). "Heathers" producer Denise Di Novi claims she had to take out an $1800 LA Times ad for the movie all by herself. Lehman also clarified, "['Heathers'] did stay in the theaters for a while, [but] it never made a profit."
The reviews were appreciative, though. Rita Kempley at The Washington Post called "Heathers" one of the best movies she'd seen that year. Roger Ebert was more mixed (he gave "Heathers" 2.5 out of 4 stars) but still praised that the film "inspires thought, and has the ability to shock."
Winona Ryder was also so proud of "Heathers" that it being a failure didn't even occur to her. As she told EW: "I didn't even really know that it didn't do well, to be honest. I was just so damn excited that it was so good. It just reminds me of a wonderful time in an actor's life when all that mattered is that you were really good in a movie."
Since "Heathers" has become so beloved, the initial failure has been washed off. There's even been rumblings of a "Heathers" sequel for decades where an adult Veronica is stuck in a new viper pit: not high school, but Washington D.C.