So Near, Yet So Farfetch'd - S1-E47
Continuity mistake: When Team Rocket takes off in the boat, it sinks. Their pokeballs float away, and Jessie says "Arbok and Lickitung are floating away!" But she doesn't catch Lickitung until Princess Versus Princess (Season 1, Episode 52).
Pokemon, I Choose You! - S1-E1
Continuity mistake: When the capsule containing the three pokeballs first opens up, you can see the names of the Pokemon etched into the balls (in Japanese). But when Ash picks them up, the names are gone.
Continuity mistake: When Jessie says, "Guess we woke up this sleepy dump," she has lipstick on, but the next scene shows her immediately having no lipstick.
Continuity mistake: Jessie seems completely surprised when she's told that Voltorb can explode, but in The Ninja-Pokemon Showdown (Season 1, Episode 32), not only did she and the others find out what Voltorb are, they were all affected by the explosions as well.
Continuity mistake: In the early episodes of the Advanced Generation series, May is portrayed as being slightly taller than Ash. As the series moves on, May is consistently portrayed as being slightly shorter than him.
Answer: He is a good guy but just found himself in a bad situation when he worked for Lysander. He didn't want him to harm Ash and his Pokémon when he was trying to get the special bond between Ash and his Greninja to work. He does leave Lysander and go back to being a good person.