I just had this discussion with DH. We don't share bathrooms normally, but he got up the other morning and (I thought) pre-flushed the toilet. So, because of his "judgemental flush" it made me feel like I needed to flush every time. However, he had thrown something into the toilet and flushed it and explained there was no judgement in the flush. (Sounds like an episode of Seinfeld, doesn't it?)
My way of thinking is this...I get up between 3-5 times a night. So that adds 90-150 additional flushes per month and I think that's just unnecessary.