Speaker Cable directionality: reversable??

if they're shielded than on the amp's end. technically this helps to avoid an influence of micro-phonics. if the level of micro-phonics or near-by power sub-station is very high the directionality is recommended. otherwise there will be no difference whatsoever.
breaking-in from the other side is total crap.

Shielded speaker cables ? Are you sure you're not confusing them with interconnects ? Why on earth would anyone shield speaker cables ?
My personal opinion : wire is not directional. Interconnects may be directional, due to shielding only being grounded at one end.
Speaker cable directionality is nonsense UNLESS there's some sort of network box on the cable (MIT does this I think). It's an AC signal ... that means it goes equally in each direction.

HOWEVER ... if it bothers you then just hook them up in the direction indicated and leave them alone. Why even bother to try them in the "wrong" direction, other than to satisfy your curiosity ? And you can't satisfy your curiosity by asking our opinions .. you'll only do it by experimenting yourself. (Which I have done, just to see if it does make a difference ... I certainly couldn't hear any).

If I were you I'd hook them up in the "correct" direction and then leave them alone and enjoy the music. I'm certain that they're not directional, but from your question I just know it's going to play on your mind if they're the wrong direction. Sooner or later you'll end up changing them.

For those who tried to answer my question, your input was appreciated.
There's no shielding or anything fancy, just the XLO-label shrinkwrap covering the spade terminations have directional arrows on them. My instinct (reasonably enough) is to follow what would seem to be "manufacturer's instructions", but what was intended to be the "amplifier end" has spades, which won't work with my amp. As I said, hooking them up in accordance with the labelled arrows would require me to cut off the spades, so there's no way to just try out which sounds best.
"Seandtaylor" seems to have posted without actually reading my question, as curiosity isn't even an issue, and it's actually impossible to just hook them up in the advised direction (unless I cut off the spades).
To everyone else who weighed in with advice, THANKS!!

Keep in mind that some manufacturers put arrows on their cables to cash in on the impression that "directional" cables are better. I'm with Taylor on whether shielding matters for speaker cables, however.

Oleander, while it might compromise the results, you might be able to find adapters to experiment with before doing any thing drastic.