Thor thought he hated his brother. After years and years of trickery, faked deaths, and mischief… Thor thought he hated Loki. Or, at least, that's what his mind told him.
But as he watched Thanos strangle Loki, the blood draining from his face, Thor realized it. He didn't hate his brother, that's just what his brain had convinced him of. His heart, deep down, still cared for his adopted brother.
Thor couldn't bare to watch the last bit of life leave his brother's eyes, he couldn't bare to watch as Loki's still, cold body tumbled at his feet. Thor didn't see it, but he knew.
He was filled with rage. Vicious, horrible, undying rage. The kind that clouded your mind and turned the corners of your vision white-hot with anger. How dare Thanos lay a hand on his brother?! Loki deserved so much better than to die at the hands of some overpowered raisin!
Thor could feel the electricity coursing through his veins. He could feel the anger bubbling up inside of him, fueling sparks that spattered out his hands.
Thor thought he hated his brother. In the end, it was just what his mind told had him.