The Secret Life of Walter Mitty confronts that age-old question—does a movie get its drama through its plot or its characters? Its answer is to shrug indifferently, try to do both, and do neither.
It's the complete opposite of Robert Frost's "The Road Not Taken": two potential movies diverged from a famous short story. Ben Stiller took the one most travelled by. Then he changed his mind and tried to go back and take the other one, but by then it was too late.
The plot first. Walter works as a "negative asset manager" for Life magazine (product placement). He develops pictures taken by ace photographer Sean O'Connell (Sean Penn). When the magazine decides to become an Internet-only publication, his job is in jeopardy. Then he can't find a key photograph from Sean intended for the cover of the last print issue of the magazine. Meanwhile, his newly created eHarmony (product placement) account won't allow him to "wink" at his coworker, Cheryl (Kristen Wiig, looking and acting more like Jennifer Aniston than Kristen Wiig).
At this point Walter does what any middle-aged American worker facing a layoff from his job of 16 years would do: he jumps on a plane to Greenland in hopes of finding Sean and the missing film negative. This is where the movie proverbially and literally loses its way. Walter's fantasy sequences (from whence the story derives its title) disappear, replaced by a strangely unsatisfying mashup of The Amazing Race and Sherlock.
The film lost me for good in a sequence in which Walter skateboards from one Icelandic village to another just in time to see a volcano erupt and then hop in a car for the ride he rejected in the first place, narrowly outpacing the lethal ash. Walter calls Cheryl from Papa John's (product placement) in Iceland to check in. She reminds him that Iceland and Greenland are not the same place. Such romantic, witty repartee. Who needs Nick and Nora Charles when these two are around?
The plot, particularly in the latter half, is about transitioning from fantasy to reality. But the film can't seem to decide between two different script treatments. On the one hand, Walter is not a Jason Bourne type super-agent. His adventures—helicoptering, skateboarding, mountain climbing—come second to the emotional difficulty of asking the pretty girl on a date.
On the other hand, we get ridiculous flights from reality in service of cheap jokes, like when Walter manages to get past Afghani warlords by offering them his mom's cake, or appeases a suspicious customs/immigration team by having someone from eHarmony (product placement) vouch for him. The plot circles back on itself, with Walter heading off to the nether worlds, coming home, then heading out again, then coming home again. Where is he getting the money for all this? Has he saved a bundle by living a boring life? Is he putting it on Life's expense account? (No wonder print magazines are all going broke.)