Here's an example of talking conservation perhaps a little too far. [This information courtesy of The Toilet Paper blog.]
This toilet was recently featured on EcoGeek. The idea here is that, after using the toilet, you wash your hands in the little basin that sits on the back of your toilet. The water helps refill the tank for the next time you flush.
Toilets like these are common in Japan because of how they conserve water and space. But even though I like the idea of saving water and reusing, I feel awkward about (1) straddling the toilet seat to wash my hands, and (2) washing my hands in the same place where I just relieved myself. Even though I know that, technically, the water is clean, still my inner sense of hygiene calls for some, if nominal, degree of separation.