Uchiha Sasuke wondered why people believed that time travel was impossible. It really wasn't that hard. After all, he went back in time every day. The past five years easily melted away and he would find himself staring up into his brother's murderous eyes. He would look around and see the fresh crimson corpses pooling in the compound. He would feel the betrayal. He would feel the blinding fear.
He would run; his short legs pounds furiously along the street. He couldn't run fast enough. Itachi always caught him. He always said those words. He would always leave him alone.
Then he would hear that high, grating "-ttebayo!" at the end of his blond team mate's sentence. Time would speed back up to the present, and it wasn't the red of Itachi's sharingan that he was staring into, but that impossibly vibrant blue of Naruto's eyes. The fear was chased back to the shadows and a habitual smirk formed on his face. He called his friend an idiot.
No, traveling in time wasn't difficult at all. It was staying put that gave Sasuke a hard time.