Speaker cable arrows???

The answer you gave to yourself is in the word ZERO. Obviously, the way you want them directed is the way that is as good as the other way around.

are these arrows painted/printed in yellow?
if not...most likely you got fake cables
this is the approved standard by the audio industry
 

If everything was in the right direction the audible effect of reversing one cable wouldn’t be subtle then, would it?

This is ancient history, but the story goes Ted first noticed not every spool of wire of the same spec from the same supplier sounded the same. Looking into it he learned details of wire manufacture previously thought irrelevant did in fact affect the sound quality of the wire. One thing led to another and soon they were making more consistently better wire.

Around the same time he was listening and noticing the wire did sound better one way than another. No Ted was not the only one to notice this, he's just my example. You tell your story with your examples I'll tell mine with mine. Okay? Sorry. That was for the Ted haters. You know who you are.  

Now before Ted went to the time and trouble to test and listen and figure all this out wire was assumed to be the same from spool to spool and regardless of direction. No one bothered to test and listen and so the wires went every which way. Seeing as even something as simple as a speaker cable has at least two wires then when nobody cares there's a pretty good chance L could be one way R the other, or + one way - the other, or both, or neither. It was all random chance.

Its like this still today. Even though this story goes back to the 1980's. Forty years ago. Hence my Twilight Zone remark. This is how far behind the times it is to question directionality.

And yet many manufacturers (and audiophiles) are indeed that far behind the times. So of course they get their random wire chaos and cannot hear any difference. Not because the wire isn't directional. Because they never bothered to figure out which direction is better. If they had the difference would not be subtle. Not at all.

Note that none of the wiring (or fuses) or PC board traces in any of your components was likely utilized with any thought as to its directionality. None.