Kunis has a 2-year-old daughter with actor Ashton Kutcher, and they're expecting a second child soon. So she feels like she can identify with her character's need to escape a particularly horrible day. "I think we all have those kinds of days," she says. "Actually it happens almost every day. Talking to my friends it will be like, 'Oh wait, me too! Let me tell you about what happened today!"'

Mila embraces her lighter side in new movie Bad Moms

As for being a bad mom, Kunis admits that she has had her moments. She remembers one day when she decided to take her daughter Wyatt to visit Kutcher at work. "To go anywhere, you have to pack all this stuff up in anticipation of everything going horribly wrong with the first baby," she laughs. "I was like, 'I did it!' I put her in the car. Like, I high-five myself. Then I'm driving down the 101 thinking, 'Oh my God, I'm doing really good today.' She was being really quiet, and I was like, 'Oh, let me look in the rearview mirror to make sure everything's OK.' And I look, and she's happy as can be, but just not nearly strapped in. She's just fine in her car seat, but nothing, no strap whatsoever. And I think I just turned white."

After punishing herself for making such a silly mistake, she says she finally was able to get some perspective. "Lo and behold, a year later, I came to get Wyatt out of the backseat of the car," Kunis says "My my husband had put her in. And as I went in to get her out, I opened the car door, and she's not strapped in whatsoever. And I was like, 'Thank God.' I wasn't alone."

This is what Kunis thinks audiences will enjoy about Bad Moms. "People like to know they're not alone," she says. "It's something you have to put humour in and make light of. If something's going wrong, I call my best friend and I'm like, 'I don't know, this colour is coming out of her nose and I'm pretty sure she's dying!' And it's OK to do that now, but I don't know if it necessarily was OK when my parents were raising my brother and me."

Watch the trailer for Bad Moms here: