Eh, I have the opposite problem. I consider myself thrifty, but my wife is a downright miser. If I come home after dark, I'm lucky to find the house in the dark. She'll have one tiny light on, only in the room she's occupying. If I'm working in a room and leave for 30 seconds to get a tool or whatever, she will have somehow sensed it , materialized in the room long enough to have turned the light off, and disappeared without my ever seeing her. I get really frustrated when it's a flourescent light -- I've always heard they take more electricity to start up than they use burning for a minute or so, and I've tried to explain that to her, but no light can remain on for more than 15 seconds if no one is there.
Once, when I had something bulky to carry into the house, I carefully went along the route and turned on lights so I could see where I was going. By the time I got the item out of my truck and started towards the house with my hands full, every light had been turned out.
I finally figured out a good use for this quirk. After I use my gas grill, I let it burn for a while to clean it. But, I've been known to forget that it's on. Now, when I sit down to eat, I simply turn on the patio light. Even in broad daylight, my wife will sense that it's on and repeatedly ask me every 2 or 3 minutes why that light is on. All I have to do is associate the light with the burning grill in my weak synapses, and there is no way I'll ever forget to turn it off.
In our home office, we have two desks. I had two high-hat flood lights installed in the ceiling to shine down on the desks. Unfortunately, I had them both put on the same switch. When I'm working in there alone, it drives her nuts that both bulbs are lit. I won't make that mistake in our new house...
To be fair to her, I have to mention that I have a quirk about drawers and doors that are slightly ajar - I like them shut tightly. So, we prove our love for each other in a simple way. I know how much she enjoys turning out lights so I leave them on for her, and she knows how compulsive I am about pushing drawers and doors shut, so she kindly leaves them ajar for me. Both of us are happy.