Do you feel that people in Google are more or less egotistical than other engineers you've encountered? Or is it a culture where people are willing to teach others without making them feel stupid that they don't know X?
There's really no way to answer that question without making a gross generalization. There are some programmers at Google with outsize egos (although to be fair, they often have outsize accomplishments as well). For the most part, though, the culture rejects the chest-thumping brogrammer type. Your performance reviews are done by your peers, and so if you continually make your peers feel stupid, it will be hard to get promoted. Also, virtually everything is done in teams, and you're judged by what your team accomplishes, and so it's to your advantage to raise the level of the people around you.