This is not exactly a pump story but it does illustrate the impatience of some folks.
We were leaving Zion NP and stopped at the dump station on the way out. After dumping we pulled forward to load some potable water. We had the toad attached so we were still rather long and impinging on the spot where you'd want to be to dump.
Well the guy behind me decides he's in such a hurry that me loading water is going to ruin his vacation. He pulls up behind me, hooks up his dookie tube, stretches it like a banjo string and just makes it to the hole. You can imagine what happened when he pulled the valve on the black tank....Poo Party!!! I could barely contain my laughter. Needless to say he had to spend a bunch of time not dumping and cleaning up a mess. There are some jobs that should not be rushed and dumping the black tank is right at the top of that list.
Chill.