It's really annoying to set up a dist-upgrade, leave it overnight, then come back in the morning to find out that it's waiting at 10% done so you can click "ok" in a debconf window. So, you click ok, come back in an hour, and it's stuck at another dialog. After about 5 iterations of this, you've FINALLY upgraded.

dist-upgrade should either queue all dialog boxes until the end of installation, or anticipate them beforehand so you can click through them all and then leave.