Why didn’t I get the interview, I’m perfect for that posting!!
Okay settle your perfect self down. And don’t pout! Listen, a big part of this is the process. The line manager spends next to no time with HR discussing the need, HR writes up the posting as best they can, (or cuts and pastes from the last posting, don’t get me started) and then YOU take it literally, and shape your resume based on the posting.