Empty Catch Blocks
A normal user is going to click your button.
The user won’t see any kind of error message, which is maybe what you intended, but on the other hand, the button will seem to do nothing. The user will have no way of knowing whether she did anything wrong. The user will try it several times out of desperation. Then the user will attempt to contact you… No, actually that part may never happen. Then the user will close your app and go to bed because there is no conceivable way to determine what’s wrong or even if there is something wrong, and it’s literally too much trouble to ask. You’ll never know there’s a problem until nine months later when the user has to call you about a completely unrelated matter…
