IIRC, most crashes are due to poor driver implementations, and other software bugs. I can't think of a user interaction that would crash a system, unless they physically beat the hell out of their system causing damage to spinning rust.
I get what you're saying, but often the bad drivers are because users are installing non-recommended drivers to begin with. Or installing known buggy software that experienced users like us would have avoided.
I've seen users place PC and Macs next to radiators or surround their device with folders and reference books, oblivious to the fact that computers can overheat and need ventilation.
I've seen users trying to use Excel as a database, then get impatience when Excel starts hanging or Windows starts running slow, and retaliate by pressing more buttons more rapidly thus locking the entire OS up.
I've seen users who would just switch the power off at the wall even night. Overtime NTFS would corrupt to a point where random crashes would happen.
I've also seen people physical attack - kick and thump - their computer when it runs slowly, an application crashes, or just through bad temper. This can damage the HDD and lead to more crashes.
There are also users who think they understand computers, so they like to tinker with lower level settings (IRQs, paging, CMOS settings, driver options, etc) then get surprised when things behave unexpectedly.
Most recently though, I had to explain to one guy who installed his own motherboard and accidentally cut a deep scratch into it, why his random crashes are potentially his own fault.
So I definitely blame users for most PC crashes. Even with the few number of kernel panics I've had over the last 15 or so years, I can attribute most of them to myself. eg I was experimenting with undocumented Windows APIs to change low level behaviors. Or I was experimenting with running non-supported file systems as my main OS drive.
