been through four Google loops across my career. the behavioral round is the one most people underprepare for because they assume it's easy, and then they blow it because they don't understand what Google is actually scoring.
Google's interviewer scorecard uses four values dimensions: Googleyness, General Cognitive Ability, Leadership, and Role-Related Knowledge. the behavioral round primarily hits Googleyness and Leadership. knowing this changes how you prep.
Googleyness at Google means: you're comfortable with ambiguity you act without perfect information when needed you 'lift others', as they put it, not just yourself you're honest when you've been wrong
the questions that show up consistently: tell me about a time you disagreed with a decision and had to implement it anyway tell me about a project you took from ambiguous requirements to shipped product tell me about a time you failed (and what you did after) tell me about a time you influenced without authority
what trips people up: telling stories where they're the lone hero. Google is allergic to people who take individual credit too aggressively. even if you led the thing, frame the story to show how you enabled the team. this isn't spin, it's what they actually value.
also: the 'why Google' question comes up more often in behavioral rounds than people expect. 'great brand / good comp' is a terrible answer. they want to hear something about scale, about impact, about a specific product area you care about. do the homework.
I've also seen people get dinged for being too vague. 'we improved the process significantly' is meaningless. what was the business impact? how do you know it worked? numbers whenever you have them.
struct your answers with clear situation / action / outcome. you don't have to say 'STAR' out loud but they're scoring you on that framework even if they don't tell you that. 2 minutes per story, max. they will cut you off if you ramble.
the interviewers are usually ICs or managers who have been trained, not HR. they can tell when you're reciting a polished answer vs actually talking about something real.