In Away We Go, Burt (John Krasinski) and Verona (Maya Rudolph) are an unmarried 30-something couple expecting a baby. Like all first-time parents-to-be, they’re full of anxieties. Burt worries that Verona won’t marry him and make their family “official”; Verona, who lost her own parents years earlier, wonders who will help them through the process. So perhaps it makes sense that, with such concerns about how they’ll fare as parents, they’d want to feel better by spending plenty of time with some of the most grotesquely messed-up parents you could imagine.

Screenwriters Dave Eggers and Vendela Vida have concocted a road comedy that’s immensely frustrating because the good stuff is so good. The scenes that involve only Burt and Verona are almost uniformly superb, full of both snappy patter and genuine emotional connection. Rudolph is particularly terrific, dialing every potentially broad emotion back to a register of compelling maturity. In short, she feels fully and consistently real.

And she’s a stark contrast with pretty much every other character. Burt and Verona’s cross-continental journey begins when Burt’s parents (Catherine O’Hara and Jeff Daniels) reveal that they’re moving out of the country right before their grandchild’s due date, oblivious to their son’s dismay. Allison Janney and Jim Gaffigan turn up as friends who loudly lament their terrible marriage and insult their two children. Burt’s New Age-y pal LN (Maggie Gyllenhaal) and her husband (Josh Hamilton) bliss out over their unconventional parenting choices. And they all exist strictly so that we can have a superior laugh at the expense of their ridiculousness.

Director Sam Mendes has a knack for salvaging smug screenwriting (see: American Beauty), and there’s a great late scene involving Burt consoling his brother (Paul Schneider) over being left by his wife. When Eggers and Vida abandon their circus of condescension, Away We Go soars. Too bad they couldn’t find a way to explore universally human fears while also including a few more people who were recognizably … oh, I don’t know, human.

AWAY WE GO