I was in an AskReddit about unwritten guy rules and a rather common sense entry came up. The idea that, naturally, you need to allow a buffer of one urinal between you and the other guy when you're taking a piss.
As an extension, another person also added that in situations where you're selecting a urinal, you use some foresight to allow the optimal amount of people to make use of the facilities without disturbance i.e. if there are 5 spots you go for the odd numbered ones, leaving the 2nd and 4th urinals as the natural buffer.
It's the sensible conclusion and it's one that I'm sure a lot of us have come to. There is a caveat of course, if there is no choice but to take the even numbered urinals then you do what you have to, it's an unfortunate but necessary allowance. Eyes front and get it over with as smoothly as possible.
At the same time, though, if you arrive on the scene and find only the 2nd or 4th urinals in use, the natural assumption is that this guy hasn't considered his choice as well as he should have. I've recently been considering the possibility that the 2nd/4th urinal guys might have entered with the optimal spots already in use.
This makes them the unfortunate guys who not only have to experience the intimate piss, they also have to initiate it and choose which two of the three guys to disturb.
And then on top of that, once the original three have finished up and gone about their business, a new arrival sees Mr. Even Urinal and, without any consideration for what circumstances lead him there, condemns him.
The dude just can't win. He does what he does out of necessity and is reviled as a monster. By the existing pissers as an instigator with no self control and by the newcomers as a buffoon with no foresight.