why do people feel the need to buy expensive cable

Matt M. stated the following:
"I spend my audio dollar mostly on equipment, rather than cables. I buy cables that allow me to feel much more connected to the music, and I dismiss the rest. I use for MY system (made up of all separate components) low to moderately priced cables... Morrow Audio and used Nordost cables. The used cable market is very good btw. The right cable for any ones own system will vary greatly by sound and cost. IMO".
regards,
Matt M

Had to laugh because this is exactly what I use for my system.

So many components, combinations and cables. Find what works, what you like and enjoy it. Best advice is that if you can't stop listening that's a great sign. If your component or cable gets you there then great. It's funny how we value the opinion of folks who will never hear our systems or who stop by for a session every now and then. Trust your own ear.

Cable does make a difference, especially for badly designed equipment (eg: anything that is not mass market tends to have design issues).

Tip: Mogami cable are the best bang for the buck cable for the mid to high end speaker and interconnect cables.

I beg to differ. 

1.) Good cabling makes a good design even better. Cabling are sometimes misused to correct deficiencies or to enhance a certain range. Until one has experience really great cables, I don't think one can make the statement you just did. Why on earth would most of us who bought more expensive variants, want to throw money?

2.) >>  (eg: anything that is not mass market tends to have design issues). 
there are plenty examples in the mass market industries like the car industry that shows design flaws. Back to the audio industry: Let me ask you how many models of the high end series of mass market brands like Sony, Denon, etc proved to be keepers? Yes, just a few. Heck, even some of Nelson Pass' designs turned out to be just ok.
Your assumption that great design and quality is correlated to the quantities sold - and indeed this triggers the economy of scale, resulting in a lower price- is not always correct, it affects but it does not dictate.
I would say quality control is harder to achieve with some hand made equipment/device if a stringent QC process is not established and rigorously followed.

I have mentioned in another thread that the Mogami cable, widely used in pro-audio, offers excellent value/money in the entry to mid level market segment.

The correlation between the cost of cables vs the cost of critical components needs indeed to be monitored. Lars of NordOst used to put a NordOst Valhalla behind a RadioShack level receiver to prove his point that a (power) cord does make a big difference. It is of course totally up to the owner to decide if he/she want to spend 5, 10 or 80% of the total budget in cabling. The same rationale goes for the patron in a restaurant spending a relatively big portion of the bill on a great bottle of wine rather than on the entree. Just suggestion that the overall meal experience could be better, e.g. not spending on a Chateauneuf-du-Pape, rather on a chateaubriand, not ordering a 30 yr port after dinner but instead a better dessert,...

Each to his/her own.

I read this thread with interest. One must consider that one ought to consider the issue of cable matching as well. By way of example, an old Naim using DNM precision cables will outperform the Naim using an expensive Goertz cable - why - it's the fact that old Naims can't even be used with high capacitance cables. In terms of food analogy truffle oil on a mushroom risotto will go, whereas however much truffle one uses, it is not going to make a sweet strawberry souffle taste delicious - regardless of how much it costs. One of my best improvements was from a TCI tonearm cable to a Nordost Tyr - it was astonishing the difference that it made. Application is just, if not, more important than the amount you spend, but if one gets the right type of cable and goes up a range the sad truth (in terms of spending money) is that there usually are genuine improvements (subject to the law of diminishing returns)