Toilet lid tale: a few weeks ago I was prepping a recently vacant apt for painting and noticed that the departing tenants hadn't flushed. Having just read an article about how a flushing toilet blasts tiny toxic droplets into the bathroom air, and they can remain air-born for hours, I smugly closed the lid before flushing. Which meant that I could not see that the water in the bowl was,in fact, not emptying, but slowly rising. The inevitable happened. Which proves that even sound theories on practice can sometimes be very flawed.