Absolute fluff.

Anger had always gotten the better of him. And now there was no turning back. He wanted to stop it, but he couldn't. So he carried out the plan and paid the price. As a child the price for losing his temper was small, now it was the ultimate price. He'd gone too far this time, he knew it, he knew he deserved this. He just wanted people to know he was sorry. And he did so in the only way he knew how.

The Avengers were all in the kitchen of Stark Tower when suddenly they all heard a voice echo around the room.

"I'm sorry."

Yep absolute fluff.