The full meaning of his words only settled upon him halfway through.
It stopped Thor, conjured different memories of years so long passed instead of merely those of his brother. More than just the way they had all rode so brashly into battles. Heady young arrogance had been companion to them all in those days, himself the worst offender.
For he had surely courted war, courted battle and violence and glory without restraint or wisdom.
He had also courted her.
The flickers of what memories rose both calmed and hurt. It laid another weight upon his heart, a dull ache against the other burdens he carried.
They had been bright and brilliant. Something exciting and wonderful and so right. Young and foolish, they had loved with unbroken hearts. It was light to think of the joy those days had held.
Yet it cut deep with the knowledge that those days were so far over. Back when he could never have guessed the things his brother was capable of. When he could not have predicted this future if he had been given a thousand tries. Nor were he and Sif what they had once been. She was still dear to him - he would not have her anything else, but the length of those years between suddenly rang like a sharp loss. His eyes saw nothing of the dark sky he stared at. They all had changed so much and Thor found himself still struggling with his own changes.
Sif had not needed the lessons he had. No one had needed to intervene to tame her ego; she had learned it on her own. She had been wiser even in her own untamed wildness. Had she not corrected and taught and stood firm in her often too right arguements so many times over the years? Had she not been the one with most loud objections on that day they trespassed into Jotunheim?
She always had been blessed with clear sharp eyes.
She might be War but it seemed he was its fool.
And as quickly the thoughts had overtaken him it was all wiped away. He turned to Fury's voice and went right back to his task with full focus. The past would not save him from the present. It did not hold the answers he needed.