If you've avoided sandboxing issues with currently-shipping software, you're lucky. I run into them all the time. Nearly every aspect of the Mac requires priv's now, so the issues are hard to sum up. Some of the common ones are: editors that need to access sibling folders of a project, which they can't do without presenting a dialog, and editors requiring permissions to, for example, listen to keyboard events, which also requires a dialog. "Well, a dialog box isn't onerous!" I hear you say. The thing is, when an operation fails, half the time an app doesn't recover properly, and the action you wanted to finish is just cancelled. That puts a mental tax on the user, because he or she has to figure out if the action was aborted or not, or if the app needs be quit and relaunched to recover. This isn't one app I'm talking about, either. For me, this is a common occurrence. Maybe I'm unlucky.

Then there are sandboxing issues that ended or hobbled previously-shipping software. Backup utilities, software that customized system software, security tools, etc. That's not as apparent, because all we see are the blog-posts of their sad developers.

To be fair, sandboxing is probably the best way to keep a machine secure. It does make my Mac less enjoyable to use, though.