Me too.
The most annoying misconception is the idea that the reason Hollywood doesn't make very many original movies is because there just aren't any original ideas out there, and out of the zillions of professional and aspiring screenwriters, hardly any of them have any ideas, poor things. So if you have a really good idea for a film, that's gold dust and people in the industry will be desperate for it.
Any writer very very regularly gets relatives or random people approaching them saying "I've got an amazing idea for a movie, you should write it, and we can split the money!"
Then when you go "what exactly would your job be in this to deserve money, given that 'person who came up with a one-sentence idea" is not a job'" then either just blink at you, or they blithely say "just tell them to hire me as producer or director", like okay sure if you go away and spend 10 years building up a career as a professional director/producer first.
Ideas are worth nothing. Absolutely nothing. There's no shortage of amazing ideas, the only reason Hollywood doesn't use them is because they're scared they won't sell and would rather invest in proven IP.
Every screenwriter on the planet (including screenwriters working to a high level, with a great CV and connections) has a whole stack of original screenplays which are probably brilliant, but which they can't get produced. The Blacklist exists for this very reason.
And that's screenplays, not just ideas. Coming up with the idea is the easiest bit. Writers come up with 50 ideas before breakfast. Picking just one, translating that idea into an actual outline, figuring out the complexities of plot and the various subplots, creating interesting and multi-dimensional characters to go along with this great idea, then actually writing it. Then writing the 10 or 20 drafts necessary. That's the hard part. That's why hardly anyone with an "amazing idea for a movie" actually does anything with it.
The other example of this is people who have read a book, loved it, think it would make a great movie, and bafflingly think they deserve a movie deal and lots of money just for saying the words "you should turn this book into a movie."