I'm not sure if they count as rough edges, but most common things I've come across tend to be security related and the limitations on a normal user. From (foggy) memory you can't sudo by default, and you also can't mount as a normal user. These things are probably perfectly reasonable choices to make for a secure server but annoying for a desktop.

This may not count as desktop, but another annoying one is /usr/sbin and some other common directories being missing from the default PATH.

Still, it's way less annoying than ubuntu's constant nagging about updates and trying to shove snap in your face.

For me it was outdated browsers, i switched from Ubuntu just for Chromium and was shocked when i saw the version available, not just Chromium but also Firefox, they backport fixes but don't release new version to stable channel. Not really comfortable using Unstable/Testing channels which my have newer version.

It's also hard to download first time you want to install, coming from Ubuntu there is just one x64 .iso and one big "download" button that auto select the right file. In Debian i had to google which file to download from CDs and DVDs version just for x64.

And there is the install UI, it give you a 2006 vibe.

This small things are easy to fix but still there for some reason, probably because they focus on core and more important stuff, but this are great things to have for new users.

Similar to what flukus said, the default configuration is surprisingly minimal in some cases and surprisingly sophisticated/messy in others. And for a desktop user everything is kind of a bare default experience. And that's not to mention the ancient package versions, but if you're a moderately experienced desktop user you might want to consider using Sid/unstable anyway.