DH insists on leaving the landing light (also 20w low-energy) off overnight, because it shines under the door; and in fact he turns off hall or landing light if he finds them on during the day even though:
a) this is a mid-terraced house so quite gloomy indoors
b) these bulbs use an hour's worth of electricity warming up when switched back on after having been needlessly switched off
and (the clincher)
c) he turns on - and leaves on - the bathroom lights (3x50w halogen) even when the sun is streaming in (bathroom has E & S windows and is dazzling most daytimes )
I just whinged at him for turning the hall light off on his way to bed yet again, and he bumbled and mumbled about "light pollution" - WTF???