disk activity lights can be pretty keen when you're trying to figure out whether or not the system is entirely halted or just slogging through a heavy workload.
the kind of time when a tool that is good at measuring such things won't ever even attempt to load.
I also enjoyed the sound that the HDD made when something was happening. So even if the computer froze, the sound gave me a bit of hope. If there was no sound from the HDD and the computer froze, I just restarted the computer, abandon all hope.
I understand this; on the other hand I pretty much want a totally quiet computer, so I don't really miss the sound. A frantically blinking LED is useful, and desirable if not too bright.
the kind of time when a tool that is good at measuring such things won't ever even attempt to load.