Ash, Ash, Ash...so many years of Pokemon training, and actually having Pokemon all around you, and you still haven't mastered the types and what not. I know most types match-ups, and it took me a short time to memorize everything. MUCH less time than you.
And yes, Ash is so annoying when he pulls out a Pokedex for every Pokemon. I remember there was this Pokemon in Advance: Battle that he saw, like, twice before, and he still pulls out a Pokedex. Maybe he is annoying, or maybe he knows he's on world-wide television and he's trying to show any young kids that are watching the things that he knows, and also show the people who missed the episode(s) where they previously explained that Pokemon. I mean, Meowth knows they're on a show and in movies. And in Pokemon 3: The Movie, One of them from Team Rocket (I forgot who) mentions losing their jobs if Ash dies, on that part when they prevented him from falling down the crystal tower. So they all know they're just cartoon characters. Maybe Ash knows that some people missed the episode on, say, Azumarill, so he pulls out his Pokedex again anyway.
And as said on the first page somewhere, maybe Pikachu should evolve. By now, he should be about...*counts* five and a half, or near six, if you're in Japan. And since Pokemon are like animals (besides humans), they mature VERY quickly, and Pikachu should have a better mind than when he denied evolution at the age of three. He should know all about evolution by now, and he should evolve. If he wants power, that is. But maybe he's trying to prove that he doesn't need to be evolved to be super-strong. We don't know. But if we're bringing up this issue about Pikachu's evolution, how come nobody mentions Bulbasaur? He refused to evolve, as well.