Specifically, that in a town obsessed with youth, career opportunities generally decrease with age.
"By the time you're 40 in Los Angeles, you're over the hill in the business," Griffith, 58, tells PEOPLE. "It takes women that are strong enough to actually change the perception."
Griffith, who was nominated for an Oscar in 1989 for her performance in the women-in-the-workplace empowerment classic Working Girl, cites Zoe Cassavetes, the director of her latest film, as one example.
Day Out of Days sheds light on what it really takes to survive in Tinseltown. Griffith plays an unstable mother/momager to 40-year-old actress/former in-demand starlet Mia Roarke (Alexia Landeau), and emphasizes that the film rightly shows the less-than-glamorous side of the business.
"People should know it's really f---ing hard," she says. "It's tough, it's not glamorous like it's portrayed. Some of it is glamorous, but honestly, unless you can really enjoy your work, it's too tough. The payback is being able to play and do your job and have fun with it because otherwise it's just too brutal, there's too much judgment and criticism, opinions, it's just brutal."
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She says that's true even when acting is the family business.
Now, Griffith is passing along what she's gleaned to actress daughter Dakota Johnson. Griffith says she and Dakota's father, actor Don Johnson, try to be as honest as possible about the reality of working in Hollywood, while also encouraging the Fifty Shades of Grey star to find her own way.
"She is very strong and she's charting her own course," says Griffith. "But she does listen to her dad and I just try to stress to her that the most important part is enjoying the work and having fun and for her to really be enjoying this time in her life because it's not always this great. As great as it is for her right now, she's going to have times where she's really not having any fun, you know? It just happens.
"It's a very strange business because you either have the magic or you don't," she continued. "It's not anything you can learn from anybody. The camera either loves you or it doesn't and that's the part that's really hard and sad for many people – they just don't have that thing. Dakota has got that thing all over the place, she's just magic in front of the camera, she was born that way, it wasn't an acquired thing."
As for Griffith, the veteran actress claims that right now she's having a ball.
"Oh my God, it's so much more fun now because now, for me, I don't have the [pressure]," she says. "I look at Dakota now and I see how fastidious she is being and how careful she is being about the way she wants her career to go. She's really smart about it. For me, I feel so grateful that I don't have to worry about that anymore.
"All I can do and want to do right now is do great parts, play great parts with great stories that are attractive to me, like Day Out of Days," she adds. "Who knows, maybe I'll get a big movie again. But it's not about the manipulation of the career anymore, it's about doing the work."
Day Out of Days is now available on Digital HD and On Demand.