What I don't know: why these movies keep getting made. I Don't Know How She Does It is based on Allison Pearson's 2002 comic bestseller and directed by Douglas McGrath. But its real auteur is screenwriter Aline Brosh McKenna, scripter of wan workplace romantic comedies such as The Devil Wears Prada and Morning Glory. Kate Reddy (Sarah Jessica Parker), the protagonist of I Don't Know How She Does It, must balance even more than the heroines of McKenna's earlier films: a career in hedge-fund management, a spouse, and two young kids. In both her home and work life, Kate constantly anticipates needs and strives never to disappoint, impossible expectations that she tries to meet with ever detailed logistics — planning that becomes even more complicated when her job demands that she travel to New York frequently to work on a project with a colleague there, Jack (Pierce Brosnan). How does Kate do it? She is strong, she is invincible, she apologizes a lot, though every time she's quickly forgiven, notably by spouse Richard (Greg Kinnear). In a significant departure from Pearson's book, Kate doesn't have to make any real compromises to fulfill her husband's and children's needs and her own commitment to a job she loves. It's not the place of I Don't Know, a mass-market diversion, to proffer real solutions to intractable problems. But wouldn't the film serve its intended audience — moms who do it all — better with more messiness and less fantasy?