According to producing-and-writing duo Seth Rogen and Evan Goldberg, it took countless meetings with studios and "years and years" to get the green light for their hit 2007 comedy "Superbad."
In fact, Rogen said Saturday at the Produced By Conference at Warner Bros. Studios in Burbank, he was originally going to play Seth (Jonah Hill's role) but it took so long to get to make the film that he "aged out of the part."
But Rogen, Goldberg and their producing partner James Weaver said that even with the difficulties that go with getting a film made, the wait is usually worth it.
"If you like really like it [your project], don't give up on it," Rogen told attendees at a panel discussion during the event hosted by the Producers Guild of America.
The three, who generated lots of laughs throughout the discussion, shared their filmmaking experiences and tips. Rogen and Goldberg said they have been collaborating on projects since they were 13, when they met each other at bar mitzvah class.
Since then, the childhood friends and their close group of collaborators -- including Weaver and director Judd Apatow -- have made a large number of R-rated box-office favorites, including "Pineapple Express," "This is The End" and "Neighbors."
Calling the MPAA ratings system "weird" and "stupid," Rogen said that making R-rated movies is less limiting. "Life is R-rated ... no matter what you do," he said.
Like many others, they said, they learned what works best and what doesn't work at all through trial and error.
For example, Rogen said, with the 2011 action comedy "The Green Hornet," the filmmakers "learned not to make $200-million movies. It's not fun."
The three also said that it's important to draw from personal experiences when writing projects.
"We stick to what we know ... relationships with our wives, our friends" Goldberg said.
Though they said making movies is fun, Rogen and Goldberg agreed that producing is the most difficult task.
"Raising money is "the step that sucks," Rogen said.
Asked about upcoming projects, the filmmakers said "The Interview" (starring Rogen and James Franco) is now in post-production.
They also said they are working on a Christmas Eve movie directed by Jonathan Levine (who they worked with on "50/50") and are developing an animated film called "Sausage Party."
The panelists encouraged attendees to pursue their own projects.
Citing platforms such as YouTube, Weaver encouraged the crowd to utilize various resources to create projects.
"Distribution is at your fingertips," he said. "We literally have cast people off YouTube."