Here's an interesting reason why so many (around 9 percent, according to the most recent data) iPad and iPhone owners don't use apps as often as you might think: one bad experience usually ruins the whole setup for them. That's according to a new survey done by Harris Interactive, which found that 38 percent of mobile app using adults polled were actually dissatisfied with "most" of the apps they'd used. And 69 percent said that using an app they didn't like actually colored their perception of that brand entirely. Thirteen percent said that any bad app hindered them from even downloading other apps. You can probably imagine a user pulling up a fart app recommended by a friend, realizing how dumb it is, and then dismissing the App Store entirely.
Of course, this survey doesn't seem to specifically cover the App Store (and it only surveyed 781 people, though we'll hope Harris chose those people as a representative sample), so these people could have been using non-iPhone mobile apps -- typically a far cry from what's available in terms of selection and quality on the App Store right now.
It is interesting to hear some reasons why people aren't downloading and using apps. It's weird to think that people would use a terrible app and have it color their perception of some of the great apps we love, but as new as this platform still is, mass market users are still forming their opinions about the concept of applications on their phones.