Not for myself but a client who was running a game server. He wanted to tweak the number of ticks/second that the kernel interacted with CPU. Didn’t even know that this was a parameter and after a few attempts, according to him, never went on that server myself, made a huge difference and he claimed having grabbed a good part of the market because of that.
After that familiarized myself more with the stuff in there. But that was a good while ago, before most of you guys were born.
Surprised nobody mentioned Yakuake. Just discovered it’s just for kde. Been using it for years. It hides at the top of my screen and slides down when the cursor hits the top. Full desktop when not used and can access it no matter which app I’m using.