I like the way kdenlive recovers from a crash
Picks up rendering & all the clips from where you left off
I wish I could close a session of partially finished stuff without bothering with projects & such

I've used KDE for more than a decade
Not just the desktop but the Ksuite of programs
Being able to setup a nice custom tool bar
Auto hide panels of a size that my decaying eyes can read
Doing update without having to troubleshoot afterwards :D