When asked the question of whom he admired the most, the answer usually shocked him. He would like to say he most liked the hero who gallantly saved the day any way he could, or even the one who remained loyal by his side while still being of use. He wished he looked up to the mentors that guided them or even the innocent bystanders who were dragged into the fray and proved their worth. He wanted to admire the courageous, strong and smart.
However he had his reasons for not admiring the hero or the sidekicks or the teacher. The almighty hero was still a slave to his own destiny and was too noble to do anything about it. The sidekick, while abundant in his own heroics was still forever doomed to be in the shadow of those above him. They were all still controlled in the end.
That was why Ryou admired Seto Kaiba the most. He was in control of his own fate, and answered to no one. He wasn't a coward, nor weak. And the bottom line was, he was the opposite of Ryou, and exactly the kind of person who could best withstand having the Thief King in his head. Unlike what Ryou did. He was weak; everything he despised. He wanted to be the one who could be admired, but he knew that was never going to happen. So he would just have to settle for admiring from afar.