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
"Why do some people insist on telling others how to spend their money?"

I agree. But nothing wrong with discussing controversial topics that matter and being an educated buyer. If that means buying $5000 wires for someone, so be it.
I do believe that effective shielding against noise IS perhaps the most valuable function that any wire can provide that is most likely to make a difference in sound quality in many cases. I've found Pangea 14 series to accomplish this most effectively, as designed and advertised. I'm sure many others do as well. Its not rocket science and need not cost a fortune IMHO.

The fact that Pangea and I am sure others CAN accomplish this for fairly modest cost is something worth noting.
There are volumes of research on why people buy luxury goods. High end audio is a luxury item and within high end audio expensive cables are even more of a luxury. The literature is pretty clear on a consensus view. Buying a luxury item makes someone feel good about themselves. Whether or not the cables out perform lesser priced cables is somewhat besides the point as long as the buyer perceives them as a good value. Whether or not someone else considers the purchase to be a good value is also besides the point. In some cases, external criticism of the purchases reinforces the purchaser's positive feelings.
By and large, according to many reviews and many comments by individuals, and regardless of whatever silly arguments naysayers might come up with, the more expensive cables are the best sounding cables. That is not to say that the most expensive cables on Earth are the best sounding ones, necessarily, but they should get you into the ballpark. By the same token, if you purchase some High Fidelity cables they should At the very least get you on the ball park. Of someone is sporting some $105,000 Rockport Hyperion speakers and a $102,000 Walker Audio turntable what's the harm in say $20,000 worth of cables? I don't begrudge anyone buying a $205,000 Ferrari California. Live and let die, I say.