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]
(..) The next wave's gonna hit any minute. What have you got, Stark? Well, nothing great. Maybe a way to blow up the city. That'll keep it from impacting the surface if you guys can get clear. I asked for a solution, not an escape plan. Impact radius is getting bigger every second. (..)2015 Avengers: Age of Ultron
(..) It's beautiful. And SHIELD never even thought... The most versatile substance on the planet and they used it to make a frisbee. Typical of humans. They scratch the surface and never think... ...to look within. - I'll take Natasha and Clint. - All right. Strictly recon. (..)2015 Avengers: Age of Ultron