One Man and His Dog (1999)

Kees (Ramsey Nasr) is a gently eccentric loner who takes his imaginary dog for a walk each evening and likes to listen in on his neighbors' conversations. He is lonely. He has no real family, as his father is dead and his mother is institutionalized. However, when the chronically unemployed Kees gets a job at a bank, many of his co-workers don't know what to make of him, and scarcely anyone talks to him -- until the day someone comments on a photo in his wallet. Though he doesn't actually know the woman in the picture, Kees tells them the woman in the photo is his girlfriend and starts spinning tales about their "relationship." Before long, Kees has invented an entire alternate personality and is stealing photos from others to fit the new "friends" and "family" he's created.