Many people feel uncomfortable talking about their car problems with mechanics. Women especially feel that they have unfair advantage taken of them because they are not conversant with the technology. They might not understand how the machine works, so they are hesitant to authorize repairs on something they never heard of before. Men might be reluctant to admit that they don't understand the new technology, especially if they did understand it in the past, and a technician is telling him he needs a new widget, without telling him why he needs it. Sometimes those feelings are justified and sometimes not. Let's see if we can shed some light on the subject and give some pointers that may be helpful for the next time you have to deal with it.
Mechanics are trained specialists in a craft that, like all crafts, has it's own language. That language becomes a shorthand means of communication between brothers of the guild, speeding the transfer of information among themselves -like other techs, supervisors and parts people- and pride is taken in the mastery of the language. Think about medical terminology. If you've ever heard two doctors talking, you probably wondered what language they were using. It's because it is not necessary to completely explain and describe things that are already understood by the other party. In fact, it might be insulting to do so.
However, (and it's a big however) knowing these secret languages does not excuse the speaker from using more common language when speaking to a non-specialist about a specialty. When doctors fail at this, we say they have poor bedside manners. When mechanics do it, we say they are arrogant jerks. When computer nerds do it when explaining my smart phone to me, I think they are trying to show that my phone is smarter than I am, and I don't like that, even if it's true.
A truly valuable technician is one who can translate from his specialty language to laymen's terms, without patronizing or talking down to you, no matter what his specialty. It might take a while for a nuclear scientist to explain some part of his craft to me, but if he really understands his work, and understands common language, he can do it. If he is too lazy or arrogant to try to do that, then he is a jerk. It has nothing to do with intelligence, except that more intelligent specialists can do a better job of translating to layman language.
The point here is that you don't have to take it from jerks. You have every right to understand what is being said if you have a financial interest in the problem. If it's your car and you're paying the bill, you should insist on an explanation that you could understand. If you're buying a cell phone, you only want to buy features that you will use. In some cases, the technician may not have a good enough mastery of the common language. Your choice there is to look for another technician, or decide whether you trust this one.
I have watched many conversations where the customer makes his decision, not from what is said, but from what they think of the speaker. A smooth talker may not seem trustworthy, or a tongue-tied shy person may have that honest face. We all learned the common language first, and then the specialists' terms, so we can back up if we try. Remember, when talking to a mechanic, or cell phone salesman, or doctor or insurance agent, or any other specialist that you don't have to learn their language. Simply insist that they use yours.