Overall quite subjective. You're not going to 'win' the interview every time. Sometimes the cards are practically stacked against you. You get asked a question

Overall quite subjective. You're not going to 'win' the interview every time. Sometimes the cards are practically stacked against you. You get asked a question no one had actually tested beforehand, you get an interviewer who's trying to prove how smart he is, you get someone who is too fixated on a particular skill you must have, you get someone having a bad day, etc... And when the process easily take 6 stages and unanimous thumbs up, one of these is likely to come up time to time no matter how prepared you were. Don't take it personally.