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Here's a new article that answers your question. It lists a bunch of mobile mistakes that drive users crazy.
For me, the points from the article that really stand out are #1 and #5. I feel like many mobile apps try to do too much, but are ultimately confusing. Also, I'm always turned off when a mobile app makes me register immediately, especially if they ask me to log in with Facebook or Twitter before I even use the app. I usually just uninstall the app immediately when that happens.