“All us working moms feel like we’re spinning 50 plates at a time,” says Allison (Christina Hendricks) as I Don’t Know How She Does It begins. But a special few do it better than everyone else. At least they look better while they’re doing it. Or maybe they’re just living inside movies that spin the fantasy that it can be done—especially if you whine and worry and cajole your husband and coworkers and best friends, until they too believe that you are doing it.