or that if you leave a little bit of water in the hose the pump with 500 gph at 8ft head pressure doesn't put out a thing even though all it would have to do is pump it up 3 feet and into the hose.
BUT: That very same pump being tested in the sink and without the (half water/half air hose) attached to it manages to shoot water from one end of the bathroom to the other including soaking any surprised testers.
It's true...

You know how when you make a pony tail, you use two hands for the hair and keep the rubber band handy in your mouth. I've recently noticed many of my hair accessories taste salty - evidence of things not quite working out as expected...