I'm always fascinated by how much people think Natasha shows to the outside world, because she was that combination of expressive and deceptive in Avengers. I think by the time of Captain America 2, she and Steve are tight (and how Steve responds to the revelation of secrets about her past will be interesting), but I wonder if she has any relationship at all with Bruce or Tony. And if she and Steve have been buddy-copping around, where does that leave Clint?