It’s a stochastic process. Some percentage of Google interviews are bad. As a job-seeker you are drawing a few samples from each company and you make a judgement.
The bigger the company the more variability in experiences.
So you make a decision with imperfect information. But it doesn’t really matter because even if you have perfect information through the interview that’s still an imperfect measure of how the job will be.
It’s all stochastic so the only way to get a good outcome is to iterate—guess, evaluate, try again until you find something you like.
