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
Some might find this Cable Snake Oil Antidote interesting with respect to LRC, the signal and the system.

Cables affect the sound and the effect is system dependent.

Another's opinion on a cable in a vastly different system may not be valid.
There are two very easy ways to debunk outrageous cable, "power conditioner", "isolator", "speaker cable suspender", "special capacitor", and "special resistor" claims:

1) Measure the electrical and acoustical signals with the allegedly improved "product" versus without. It's the year 2018 folks. We now have cheap devices that detect all aspects of sound (phase, pressure, frequency) at a level that is orders of magnitude better than average human hearing. What once cost tens of thousands of dollars in testing equipment can practically be obtained for several hundred with a high performance laptop, high quality calibrated microphone, and audio test suite freeware.

2) Research the backgrounds of the individuals who own and run the companies that are peddling "special resistors", "speaker cable suspenders" and the like. I've been observing this scam for nearly 4 decades and every single "manufacturer" of said products I've looked into is run by con artists and fast talking salesmen/women.  Just like there are tons of con artists peddling miracle health cures, there are and unfortunately probably always will be con artists selling magic cables and capacitors that some how fix everything that is wrong with your audiofool system.
Someone needs to use the Yellow Pages to find his local consumer protection agency representative. I’m sure he’ll help you mount a nice big lawsuit against all these scam artists. Bad scam artist! Bad! Let us know how that works out. Also, try getting a hold of NASA to see if they have time to do some testing for you. Report back your results.
" Someone needs to use the Yellow Pages to find your local consumer protection agency representative. I’m sure he will help you mount a lawsuit against all these scam artists. Bad scam artist! Bad! Let us know how that works out. Also, try getting a hold of NASA Nd see if they have time to do some testing for you. Report back your results." - geoffkait

I don't need anyone to test for me. I have a full bench of spectrum analyzers, signal generators, multi trace scopes, and a very reliable Earthworks mic that I use on a daily basis. Digital technology exploded a lot of myths. Now that it is fairly cheap and accessible, only those who actively choose to bury their heads in the sand will succumb to foolish arguments involving so called "audible improvements" that can't be measured or tested for. My microphone can pick up low frequency grumbling of a truck approaching a quarter mile away and display it on my software recording dashboard about 20 seconds before it's loud enough for me ti audibly detect. I see evidence of this every day and don't needs anyone's "veils have been  lifted" hype to tell me if there's a difference. And no neither NASA nor the BBB are necessary. All that's needed is a little common sense and a mind that's open to accept science and the scientific method.
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I anxiously await your results. I had no idea you were so handy. Now we’re getting somewhere!