Rol tells it like it is:

And finally, why is it that when you get one of the aforementioned crap-headlight types behind you, and slowing down to let them pass has no effect, they’re always going to the exact same place as you? You keep thinking, they’re bound to turn off here, they’re bound to turn off there, but no, they’re with you all the way. All the way to your office parking space, all the way home to your very driveway / garage / onstreet parking area. I’m surprised they don’t follow you inside and ask for a cup of tea. Or a cloth to polish the dirt off their headlights… just in case they’re not dazzling enough.