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
"audio as a hobby is dying, largely by its own hand. As far as the real world is concerned, high-end audio lost its credibility during the 1980s, when it flatly refused to submit to the kind of basic honesty controls (double-blind testing, for example) that had legitimized every other serious scientific endeavor since Pascal. [This refusal] is a source of endless derisive amusement among rational people and of perpetual embarrassment for me..”

-Gordon Holt
 Stereophile
Stringreen said: "...or expensive watches..."

That reminded me of when my brother-in-law bought a Rolex and was touting how great it was.  I think it was a one of the cheaper models and about couple grand.  Bottom line is that a watch is for timekeeping and my Seiko kept time just as well as his.  What he really got for his money, I guess, was a hunk of gold jewelry that said he was successful.  I'm thinking that people who, for example, buy a used pair of "Tara Labs Omega Gold" speaker cables for $7000.00 (http://www.tmraudio.com/product/xx-55) are like my brother-in-law.  They are more concerned about what "having" those cables says about them than any real improvement in speaker performance.  I have a set of pristine B&W Nautilus 803's.  I have to chuckle because this used pair of cables cost twice what my used speakers cost.
I like red wine but I tend to buy more moderately priced bottles because I can’t taste that much of a difference between mid-priced bottles ($10-$20) and higher priced bottles (+$25). There are bad low priced wines and bad high priced wines. But I would never say all high end wine is a rip off or call wine connoisseurs misguided as that would show my ignorance.

I am slowly upgrading my audio cables and like wine I do so based on MY senses, not others.
Purchasing decisions are made from various reasons. Necessity, sense of style, sense of accomplishment, appreciation of craftsmanship, pride of ownership ...  It is my observation, usually says more about the ones that criticizes the decision than the ones making the purchase.