Sasuke was a happy child, eager to please and be worthy of his family name. This changed after his entire family was killed by Itachi, the person he most admired in the world. He became cold toward others, unmoved by and uninterested in what they do or think of him, choosing instead to keep to himself. He stopped using honourifics like "sensei" or "sama," something considered rude in the Japanese language. His only goal in life became to take revenge for his family's deaths and, by extension.