If you think she only did it for the money, you haven't even 'scratched the surface'. [=there are many other factors, reasons, etc., involved]
Despite the 'surface' differences between the two candidates, they are very similar in most ways.
The tension between them is beginning to 'rise to the surface'. [=it is becoming easy to see]
(..) who gave me Francis. One spring afternoon, I discovered the bowl on my desk... With just a few inches of clear water in it... And floating on the surface was a flower petal. As I watched, it sank. But just before it reached the bottom, it transformed (..)2009 Harry Potter and the Half-Blood Prince