The back of my house faces the side of my neighbour's. They have a bright outdoor light that is on permanently, 24 hours a day. Not a motion-activated security light. If it weren't for the black-out blinds in ds's room he would never sleep as the light is so bright. It really annoys me because it is intrusive, unnecessary (safe area, difficult to access backs of houses and if you want a security light, get one that is motion activated!) and a waste of energy. I also don't think it's great for plants and wildlife as my back garden is never dark.
BUT - neighbour is a bit odd, I took ds round to ask for a ball back once and she was really off and seems to think I was impertinent even asking. she said she'd thrown the ball back (she hadn't). I don't think she'd think I was reasonable asking, AIBU?