I drive mostly on unlit rural roads and find many modern cars either have headlights that are too bright and/or perhaps badly adjusted. I also suspect that some people are driving with their headlamps on full beam all the time - the dipsticks don't know where their dipswitch is!
However the bikes are the worst because they are relatively rare so difficult to identify in the dark because of the light spread and sometimes flashing. I came across one that, when I drew level, I realised was a cyclist with a helmet lamp and another lamp low down both incredibly bright! Obviously the one on his head was shining wherever he looked. I am very pro cycling and used to cycle in London so I know about the difficulties caused by car drivers but that is not to say there aren't difficulties the other way.