oh man

LOL!! the bit about ordering throttle cables after 8000km is quite funny and reminds me how eternal patience is always in great demand when dealing with the public... in general most cables last a VERY long time and it is absolutely normal for someone to ask why you would want any part replaced.
Firstly, for Stradbiker, certainly it's possible that a cable was routed incorrectly during the dealer prep, and could be causing you a problem, but taking offense when someone asks a reasonable question only goes one step closer to altering the condition of just who is being unreasonable. Providing a reason for your request will often help them to determine if you are accurate in your diagnosis of the problem with your bike. Sure, maybe you just want the cable(s) replaced, but in that case, you should still be prepared for an inquiry or objection, and then clarifying why you are making this choice: "because i..."; or "I just want it done, please and thank you". It's always been a very effective way to for me to get things done that others may not understand my wishes for... do your best to have the dealership working with you rather than seeming to work against you.
The tone and intention of the conversation with the staff is important (one of those things that is hard to gauge in email and forums, but quite easy in person) and also the customers ability to deal with the possibility that there request may in fact be uncommon (although i have better words to subsitute for "uncommon")

I also should also mention, that you just have to accept that you will be dealing with GUYS/TECHIES in these situations, and they may be a less pampering than say the Avon lady. That's why they work on bikes. Of course not all of them are, but it might help to prepare yourself for some abruptness, arrogance, rolling eyes, argumentative personalities, etc. sorry, but it's just part of the reality of the industry in some cases.
FLYNRIDER makes an important point: definitely there are two sides to the "customer service" equation. Customer and Staff, communication, knowledge, understanding, patience, etc. etc. etc.. between people there are always at least two perspectives in a situation, and lots of opportunity for misunderstanding and mistakes, so be clear with your requests, be open to staff inquiries and everything has a much better chance of working out well.
I would also like to point out that if you consistently get bad service, then you should take responsibility for finding a better dealer, and/or consider your part in recieving the bad service. I've known customers who always require extra effort to get the correct information, because they know so little that they make big assumptions about bits and pieces and are often claim to know things which they clearly don't... so sort of cusomter who sez, "oh don't worry, the part is the same on x y z, etc." -- yeah sure they are. i've seen enough of those people in my time.
Your next step in solving the poor customer service routine is changing your approach, or asking advice from people who have had successful dealings with local dealers.
nuf said for today. keep a good attitude and do your best to help those people help you. there will always be a few good people you relate to in each dealership or at least a few in each city. you may have to chose a different brand of bike, but most of the bikes are really good nowadays and the selection is awesome.
one last note: sometimes in the service/parts department as in life, the people who are most agreeable and *appear* to be taking care of you are not the people who have your best interests at heart. There are many people who are great salesman and will kiss your butt to get you to spend more money, but more often there are less people who will sacrifice a sale to provide some hard earned knowledge and educate you about your motorcycle. These people will disagree with your and question you because they truly do know better and are trying to help you out. Often they may be frustrated by the sheer number of people that are naievly lured by the *salesmen's* "customer service" approach (i.e. the staff who sez "OK, let's replaced those throttle cables!") and they genuinely want to help you out. Remember again, they might not be impecably mannered, but they may have your best interests at heart.
oh, one last bit, bring a knowledgeable friend with you if possible. trying to do anything right all by yourself is made a lot easier if you have someone who is definitely on your side, whether they know everything or not, at least they are on your side and you can figure things out easier.
hopefully there's a few things in that posting that helps a few people obtain better service.
good luck and dont give up.
//monkey