Something I've noticed about every iPhone app I've tried is that they all have places where they seem very slow and unresponsive. It's true of the games, the free apps, the pricy, popular, "professional" apps, and even a couple of Apple's built-in apps. They all seem to have places where they take many seconds or even a minute to respond to screen touches; bog down and show a spinning beachball for seconds at a time; "queue up" input so that a button press appears to ignored only to actually do something ten seconds later like a poorly made DVR; and lock up for so long that the OS watchdog just kills them.

Because these perf issues are so widespread it seems to me that there must be some common performance pitfalls some system gotchas that are coming up over and over again for lots of different people. I'm not an iPhone developer myself, so I'm canvassing the community's opinions:

**What are the most common performance mistakes on the iPhone?** 

Or, **what human factors of iPhone development make it too easy to ship with poor performance?**