@TomF@mcc My thinkpad had an incredibly annoying feature that it would randomly dim the screen after ~20 seconds of idle time (but not always). I only just recently figured out how to disable that (it's a hidden service that came pre-installed).
I've also had no end of trouble with sleep mode. It will wake up randomly and not go back to sleep, draining the battery. It will sometimes shut itself down for no reason even when plugged in. It will sometimes refuse to sleep when I close the lid.