Anger
Brock never minded being a guiding figure in his friends' lives, but sometimes he truly wondered how Ash had made it so far in life with the lack of knowledge he seemed to have about the world and life in general. After stopping at a PokeCenter for the night, Ash had come knocking on Brock's door, hoping to talk with Brock about some unusual feelings he'd been experiencing recently. Brock listened attentively, but the more Ash described his feelings, the more Brock felt the urge to walk away.
"So, you're telling me, when you think of Misty your chest gets tight and your face gets hot, you think that means you're angry?"
Ash nodded. "Yeah."
"Okay. Do you feel like that when you're mad?"
"No."
Brock stroked his chin pensively. "Hmm. Do you feel that way when you're mad at literally everyone else?"
Ash shrugged. "No, not really, but Misty just makes me really angry sometimes."
Brock gently massaged his temple. "So what you're feeling toward Misty isn't anger, Ash. Sure, it's different than how you feel toward other people, but it's most likely-"
"Super anger!" Ash blurted out.
Brock's sigh seemed to echo through the room. He reached forward to slowly pat Ash's shoulder before walking away. "Good luck, Ash."