HAVE CABLES EVER TAKEN YOUR SYSTEM FROM SOUNDING JUST OK TO SOUNDING GREAT? Experiences ?

i am in general agreement that cable changes tend to be more subtle than major component changes as to sonic effect.  However, if you went from bad cable or cables that were inappropriate for your system and taste to something that is better suited to you the difference can be quite dramatic.  Even if a cable is well regarded and works well in other people's system, it can be well off from what is best for YOU.  For example, if you prefer/need a warm sounding speaker cable, the top end Nordost cable will NOT be for you and if you switched to something like Audio Note Lexus cable, the difference will be very substantial and favorable.

When I first started 6 years ago with my first Tube Amp from Raven Audio , Dave Thomson told me one thing you will never stop looking for more detail out of your music ..And he told me about Streaming and told me you will stop using your CD’s .He was correct....So my first test was computer in another room and needed 16’ cable to run To DAC... I purchased a Staples 35 dollar cable and said wow a lot of unusual detail never heard would not say quality...So Best Buys and Audioquest Cables I started with 400 dollar cable what a difference .. Now I had no idea at this time I would be buying a 1700 dollar cable at end to make my ears happy from a USB cable ...I know the next was a Coffee Audioquest and much more quality and detail coming from the speakers ..So decided to try the Audioquest Carbon and just a little more detail and just touch more quality to my hearing that I would keep the Carbon over the Coffee Cable...But to someone else and their hearing it could be reversed..But never in beginning would I have thought 1700 for a cable ..But sound of music is why we are in this hobby and happy ears makes you smile when You hear old songs that you listened to for years and never heard instruments or detail ever before in the  song...

Not dramatic. Subtle differences if any. I buy cables based on need - length, type of connection, build quality, reputation, reasonable price... not to change the sound of my system.  

Confirmation bias is real.  I remember a specific instance where a while back I purchased an inexpensive cable to try and then bought a much more spendy cable that was one of the "it" cables.  I put it in the system, and was able to easily switch back and forth between the less expensive cable in near real time. I thought the new cable was sounding better than the other and was quite pleased with myself. Some time later, I repeated the listening test and could not detect any significant difference between the two cables.

Which isn't to say that I don't think cables impact sound, other instances have shown that they clearly can, but my experience is more that cheap cables can degrade sound, not that expensive cables magically make your system much better.

...only when the prior set of cables was really bad, like cheaply made lamp cord, did I notice a change from something okay to something great. 

I have not heard any differences in any cables I ever tried. Based on my experience and demonstrated experimentation, not preconceived notions, I don't think cables make any difference.