He tried to kill me and Fitz. And he has actually already done that, even if I haven't had it happen yet. I could probably forgive him more for just trying to hurt me. It was because he also hurt my Best Friend. And, he didn't come out of it alright. He's alive, but I suspect in a coma. But, I won't know until the show starts again.
I can never forgive him for that.
However much he says he regrets he had to do it. I know, if he had a chance to change it. He wouldn't. He'd do it all over again, because Garrett as screwed with his head. And, he thinks he owes him.
As for Loki. I actually in some way, can't blame him for that one. I helped with the clean up after New York too. And, it caused more than just the destruction of a city. One of the chitauri had a virus, which spread to some of the firemen who had claimed the helmet as a souvenir. It caused an electrostatic charge. Killing the host, and shorting out the electrics near by. I contracted it by close proximity with the victims bodies when I examined them.
Luckily, I managed to create the anti-serum. I thought I hadn't, and threw myself out of the plane before I brought the plane down. fitz realised that the anti-serum had actually worked, and Ward jumped out of the plane after me. Injecting me with it in mid-air.