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
"Like i have stated before the price of copper is $5 a pound . So , it is not the price of the copper . What's left ? Only referring to copper cables as they are the most popular ."

The quality of the copper, and how difficult the design is to build. Have a look at this picture.

https://www.google.com/search?q=cardas+cable&safe=off&biw=1600&bih=770&source=lnms&tbm=isch&sa=X&sqi=2&ved=0CAgQ_AUoA2oVChMIlbyxtZ3pyAIVhCQmCh0Wog-y#imgrc=R76Ojp5kqP3-qM%3A
"Oh, you fell for the oldest trick in the book chief, high end audio cables." Maxwell Smart
"The quality of the copper, and how difficult the design is to build. Have a look at this picture.

https://www.google.com/search?q=cardas+cable&safe=off&biw=1600&bih=770&source=lnms&tbm=isch&sa=X&sqi=2&ved=0CAgQ_AUoA2oVChMIlbyxtZ3pyAIVhCQmCh0Wog-y#imgrc=R76Ojp5kqP3-qM%3A"

If we need to elucidate obvious aspects such as this then let's not waste our time on him.
10-29-15: Mapman
" ... in some cases, a power cord might serve a shielding function against RFi and/or EMI noise, but neither of those are necessarily a problem to start with in all cases."

I think Mapman hit a bullseye with this remark, which I think applies to all cables, not just PCs. And it accounts for why the same cable can sound different in different systems or, even, different in differing places in the same system.