The (-|+) zoom icon that shows up on the screen in the lower right hand corner. Most right handed users, however, will be using the right side of the screen for scrolling up, down, and around. I find myself trying to scroll around and instead pulling up and getting intercepted by the zoom (-|+) buttons that appear when you touch the lower right hand corner.
Would it be possible to relocate those over to the left, or even have a preferences option that allows the user to specify which corner the zoom interface should be placed in?
Help get this topic noticed by sharing it on Twitter, Facebook, or email.