This is nothing to worry about. These companies do not blacklist candidates for not getting offers. You can try again in the future. Their interview processes a

This is nothing to worry about. These companies do not blacklist candidates for not getting offers. You can try again in the future. Their interview processes are designed entirely around finding reasons to not hire someone, so much so that they very often make mistakes and reject talented applicants. It's also important to understand that there are many great companies out there. In fact, I think Amazon has a fairly controversial reputation as an employer for programmers, so you very well may have dodged a bullet. I'm really not exaggerating on that either to try to make you feel better. I've legitimately heard lots of horror stories about Amazon.