About a Boring Feature of KWin
I spend a lot of time with my face directed at my computer screen. Most of the time, I'm even looking at the screen and actively typing or reading. To help me stay focussed, I took a lesson from GNOME 3 book, then turbocharged it for own KDE setup: there is nothing on my desktop, my panel hides itself automatically, and I use the dashboard extensively. This way, most things won't distract me unless I was already thinking about them.
Sometimes, when I'm really trying to concentrate on something (which happens quite often recently), I just sit and stare for minutes on end. When I do this, I get to use one of KWin's least exciting features: the panel eventually pops up, as if to mock me for taking such a long time to think. It doesn't really bother me, but I had a hard time thinking why anybody would need this feature, since "auto-hide the panel" is not enabled by default. Then it hit me.
Months ago, a friend of mine wanted to use my computer for something trivial. I logged in, then walked away. A short while later, she said something like "what's wrong with this thing? Why is it taking so long?" As a Windows user, she's been trained to wait for some icons on the desktop or the panel with the "Start menu" on it, so when my computer just showed the desktop background, she continued to sit and wait for it to finish loading. She called me over before the auto-un-hide feature had a chance to prove its worth, but now I know, it's in there for her.