If you ever think that normal bugs are a PITA to debug, hypervisor bugs really just take the biscuit

Operating Systems do not like it when the hardware they are running on occasionally forget to behave like real hardware

Today's rant brought to you by "what happens if the CPU decides to service interrupts anyway even though interrupts are notionally disabled"

OSes also Do Not Like when monotonically-increasing timers accidentally go backwards in time, giving the OS an existential crisis about the linear nature of time