We are a consumer company and our success is directly linked to our users trusting us. Therefore we have the same incentive as the user: they want to see relevant advertising so their experience of Google is positive and we want to deliver it.
I always loved working as an actress but I didn't understand why I couldn't just opt out of being famous. And then I realized you can and I think I did. And eventually I came to understand that you can do that and also keep working.