I'm sure there are many instances of people taking more than adequate time at a dump station, but also pretty sure most don't want to spend any more time there than necessary.
I've never recorded the time I occupy the station but it's definitely longer than the three minutes as some have said they can get the job done. It probably takes me almost that long just to get the hose out of the fence post, secure both ends and hook up the water line. I guessing about 10 minutes total to dump the black, back fill it while the grey is draining, then dumping the 10 or so gallons put back in the black. I don't bother rinsing the hose...just double cap it and wait till I get home to clean it and let it air dry for several hours. I think that 10-12 minutes is a fair time and if someone behind me has a problem with that, then, well...sucks to be them.
I'm staying four nights at a FHU site this weekend so I'll time the dump process (I don't hook up the sewer hose until I'm close to leaving).
At some point during every day you suddenly realize nothing else productive is going to happen the rest of that day. For me, it usually occurs around 9 am.
Vengeance 25V (the Harley needed a home)