Non-gaming people are not all the same. What one might find useless, another might find worth in. Here are some vastly different examples that could repel different groups of people. Manhunt could repel the anti-violence crusade, Noby Noby Boy could turn off many non-gamers just because it's so open-ended and they won't get it(most gamers don't either), Civilization could turn off people for it's sheer complexity.
Overall though the best example I could give to show how useless gaming is would be to showcase everyone's newest favorite hot topic game RapeLay. I'm sure all groups would equally be turned off by the absolute horror of what they're witnessing.








