Cass felt bitter. He felt lied to. He felt pissed off.
He had wanted to come into this lesson after realising that his body was relaxing, his heartbeat was calming down, and he could breathe easily that Draken was awful at this. He wanted to be able to sit on the boulder and listen to him speak, nodding his head along with what he was saying all the while making fun of him in his head. Instead, he was staring at the man, nodding, without scowling, taking in the words he was saying.
Draken was a good teacher.
A really good one, and that was the cause of his bitterness. Cass was good at taking in information, and terrible at passing it on in any way that made sense. He was like a sponge, but it felt like he was speaking a foreign language when he tried to explain how he knew what he did.
So the fact that Draken, of all people, was good at that? Made him pissed off.