I was rejected by Adobe, Apple, Google, Microsoft, Twitter, Facebook, Amazon, Netflix, Skype and many more companies. I got rejected by Apple 3 times and two times with Facebook and Google.
I'm now working for Google.
One thing I can tell for sure, specially after interviewing others. It's all random. Most of interviewers make their mind about the candidate in seconds. If you are a charming person you have a good chance. If you are not a very likable person you have a very small chance.
Being charming, likable or whatever you want to call it is important. Technical competency should be the biggest factor but there are plenty of people who have that and are personable too.
At the risk of repeating what I commented below, I like to say the same thing differently, which seems to resonate with students in the class:
Interviewing, by definition, is not a standardized test with a standardized evaluation. On the spectrum of human interactions, it's closer to a date, than it's to a test.
In doing interview coaching/training for a living (http://interviewkickstart.com), I see this every day. It's frustrating to a certain degree, but also very powerful once understood.
I passed 3 interviews with 6 interviewers for Booking (they even flew me to Amsterdam for that). 1 of them didn't seem to like me, even before I answered his questions. The rest were very impressed (as stated in the feedback). Got rejected.
I'm now working for Google.
One thing I can tell for sure, specially after interviewing others. It's all random. Most of interviewers make their mind about the candidate in seconds. If you are a charming person you have a good chance. If you are not a very likable person you have a very small chance.