why do people feel the need to buy expensive cable


I have tried expensive cables and one's moderately priced. I would say there were some differences but I can't actually say the expensive cables were better. IMHO I believe a lot of people buy expensive cables because they don't actual trust their ears and are afraid of making a mistake. They figure the expensive cables are better for the fact they cost more. If you have a difference of opinion or share the same thoughts, I would like to hear about it.
taters
Spending crazy money on cables is not the answer.  There has to be balance. Better equipment has to usually be fed better cables. I went up the chain in high fidelity and they do get better going up the chain.  There no way I would spend more on cables than actual equipment. I have a challenging room that affects my sound as well.  Hardwood floors, odd shape and reflections. I also can only put my speakers so far apart. 

Everything matters... That said, I believe a lot of folks get caught up in the PR (b*llsh*t) techno-speak or theory, and often the bling. Yet, good sounding cabling inescapably, has research, materials, and labor associated with its cost.

In any highly resolving system and most situations, I find the choices of good cabling to be a critical part of the HiFi puzzle. 

To what Tonykay just queried, Yes really. Yes, seriously. Melbguy1 is sooo spot on!
I must say that I regretfully agree that everything matters. Last evening I listen to three ways to convert music in digital to analog on my music server. One was JRiver MC 20, another Signalyst, and the third Foobar. I was amazed that there were great differences in how about fifteen cuts sounded. Generally I find the Signalyst best but many cuts sounded better on Foobar and JRiver MC 20. Mostly these were 44.1 recordings but the quad native DSDs shined on Signalyst.

I am going no further in this quest of what sounds better. I will probably forgo using Foobar and with 44.1 will mainly use JRiver MC 21. On my many SACDs converted to DSD and new DSD recordings I will use Signalyst. There is no question that "bits are bits" is not true as all recordings passed being perfect. 

Believe me, I wish this were not true.
Most all of us agree cables are a critical part of a system but Calvin is right, you do not have to spend crazy money for cables - but you might have to spend crazy money to come to that conclusion.
Digital cables are where people are being had. $50 or so for a TOSLINK that provides good strain relief and kink resistance, DONE.