Hawkeye and Sharon Carter

For me, the best scene in the movie is the vs. between Hawkeye and Vision, because it shows the determination of the former and the intangibility of the latter. It’s awesome (and yes, I do believe that Vision was criminally underused in the movie)!
But the biggest question is this – why does Hawkeye return, when he retired at the end of Age of Ultron? What convinces him to side with Captain America and enter a war, when he’s so happy with his wife and kids? Furthermore, what happens to him next? Is he hiding in Wakanda as well? Or is he back with his family?
As far as Sharon Carter is concerned, she is basically a traitor now, after stealing the shield and the wings and delivering them to Steve and Sam. So what happens to her next? Civil War makes me believe that she will have a role to play in the future of Steve Rogers – after all, she is the only girl Captain America has kissed in a very long time (Black Widow doesn’t count, because he was, basically, forced to kiss her).
Lastly, the fallen heroes.
