"What are you thinking so much for? Were all those words just for show until now?" Arnold asked as he looked at Arthur. He wanted this guy to succumb into his palm, this was his new plan. He had always felt disgusted at this guy for acting the way he did.
How was there not an ounce of hatred in his eyes?
This was just intolerable for Arnold.
He had been living all his life in hatred, and had dedicated it all for the sole purpose of revenge. And, yet these people still treated him like this when he tried to kill them.
This was the reason he preferred Lear, he could see hatred in Lear's eyes, and it had a soothing effect on him.
It was very clear from this situation that Arnold himself was subconsciously aware of his own actions. He somewhere knew in his heart that Arthur, his mother and a lot of other people were innocent. This was the reason that he was feeling guilty somewhere inside, and that was pissing him off.