In whatever you do, there's probably some little thing that the general public doesn't understand, but which is essential to understanding your work.
When I worked in customer service-type jobs, the #1 thing that customers didn't understand is that my boss sees me every day. If you have some disagreement with me, he's probably going to take my side, not yours, whatever he might tell you.
When I teach people computers, the #1 thing people don't understand is that you don't do yourself any favors by just learning some particular program. That's like learning a phrasebook, instead of learning a language, but in a situation where learning the language is actually easier.
Now I'm in law school. The number one thing I didn't understand about American law before school, and which basically no one who hasn't been to law school gets, is the breakdown between the authority of federal and state courts.
Boring text in small font:
(Basically, state supreme courts are the highest court in the land when it comes to matters of interpreting their own law. One state might have a statute that says something. Another state might have the exact same statute. Each state might interpret them to mean something different. That's just the way it is! If a federal court hears a claim involving state law (in a mixed case of state and federal law, or because it's a suit between citizens of different states), it must defer to what that state's courts say about it. If it decides some novel question, the state courts are not bound by its interpretation. Federal courts can only decide issues of federal law and the constitution. Because the constitution trumps anything the state might do, lawyers get really creative in finding ways to turn any old argument into a constitutional question-- this is the only way to "appeal" from a state supreme court. This is also why the US Supreme Court has to decide a lot of really vague questions about "due process" and so on.)
/end boring
Is there something in whatever you do, that the general public or the press or whatever just consistently doesn't understand?