It’s a compulsion.
When a light is on in an empty room, I feel compelled to step inside and flip the switch.
It can be annoying to others. Folks here at work think so and sometimes actually say as much.
I know it’s annoying because it was annoying when my father did it. When I reach for the switch, I sometimes hear the echo of his forcible voice asking once again, “When you pay the light bill, maybe you’ll learn to flip this switch?”
So you see, it’s one of those family-imposed compulsions.