Google has a reputation for being a laid-back company that operates more like a network of startups than a corporation.
But, according to Google's human resources chief Laszlo Bock, you don't need to stress out about fitting in too much during your job interview with Google.
Just make sure you're offering ideas that bring something new to the company, and "don't wear a suit."
There are two specific things Google looks for when deciding if someone is a good fit - "conscientiousness" and "intellectual humility," as he said in a recent Ask Me Anything thread on Reddit.
Bock explains exactly what the means in his full answer posted below:
At a lot of places "cultural fit" is about "is this candidate like me." At Google, it's a bit different - we want people who bring something new to the mix. And we specifically care about conscientiousness (work to completion, think like an owner, etc.) and intellectual humility (not regular humility - just the ability to admit you're wrong). So, for Google, don't worry about relaxed vs. formal. Just don't wear a suit. :)