It's not just nerves either. All interviews, but especially FAANG ones, are random. The interview might be racist, sexist, etc. They might have gotten divorced that day. The question they ask you is something you haven't heard of but they spent their PhD on. You can even do everything correctly, but the interviewer doesn't like the way you did it.
The leetcode stuff is just masochism. You will spend X months beating DS&A into your brain until someone can pullout a random question and you immediately know what questions to ask, what steps to take, and how to write it out on a whiteboard.
The leetcode stuff is just masochism. You will spend X months beating DS&A into your brain until someone can pullout a random question and you immediately know what questions to ask, what steps to take, and how to write it out on a whiteboard.