Good Dick (2008)

A fidgety, wisecracking video store clerk develops a fixation on a particularly reclusive customer, a frequent visitor to the pornography section of Cinefile, the video store where he works in Los Angeles. After multiple failures to impress her during their brief daily transactions, he finds her street address in the store's database, drives to her apartment building and initiates an unconventional campaign to win her affections.

Source: TMDb