Near the end of the movie, there is a scene where members of the office Tom works at are interviewed (by an unknown interviewer, off screen) about what their ideal woman would be like. Tom's boss explains how he loves his wife, and admits to using some of his company's own cards, adding that it doesn't matter how his love for her is displayed, as long as it comes from the heart... Regardless of the fact that they weren't even ones written by him. Tom's friend, played by Matthew Gray Gubler, goes on about how the girl of his dreams would be a lot like his actual girlfriend, who he's been with for years. He goes on to add the subtle differences, such as a different hair color and height, also mentioning how she would have a great rack. But at the end, he offers one of the most simultaneously subtle and obvious displays of the main message of the entire movie and basically says "But, in many ways, my girlfriend is actually better than the girl of my dreams ... She's real."
"You were right all along, Tom... it was just me you were wrong about."