I've lived in Manhattan for 14 years and I've taken the G train all of one time. Whenever I see one, usually passing through some random station in Brooklyn, I consider it good luck, like seeing a unicorn. It's the most unloved train in the city.
The New York Observer ran a piece today about how the G train can ruin your relationship because it runs through a few non-gentrified parts of Brooklyn, and is incredibly unreliable, as far as public transportation goes. Unless the MTA does something to improve service, the G train, and its loveless riders, are doomed to be alone.
And then there is this video, about how the G train really can muck up an otherwise lovely date.