Funny / Pokémon Diamond and Pearl
After learning about Team Galactic's plan in Pastoria City, Barry runs after Crasher Wake to help... and then he sees the Croagunk face cutout...
Barry: Does my new outfit look good or what? Croagunk's where it's at.
And if you go around the back of the cutout to talk to him, he'll ask you why you're not talking to him from the front.
Him getting distracted by your new laptop at the beginning of the game is pretty funny also.
After a Galactic Grunt sets off the Galactic bomb at the Great Marsh, he ends his speech with this:
Grunt: Cheerio, then! (to Crasher Wake) You daft codger, your mask's absurd!
In the final Team Galactic event, Looker gives you a tearful good-bye. Cue seeing him in the Veilstone Game Corner with you distracting him, and making him lose his winning streak.
There's a running gag throughout the game that not even the members of Team Galactic seem to know what Cyrus' plan is.
Outside Amity Park, which only allows "cute" Pokemon inside, an NPC is complaining about discrimination against his Gyarados and Steelix.
In Platinum, after defeating Flint and Volkner outside the Battle Frontier, your rival tries to enter, but is interrupted when Palmer comes out of it and bumps your rival back three spaces.
When you defeat Mars at Valley Windworks, the scientist Team Galactic was holding captive is reunited with his daughter... who, while happy to see him, promptly complains that he stinks and needs to take a shower.
When you first run into Team Galactic at Jubilife City, they are trying to threaten Professor Rowan for his research data. Instead of being afraid, Rowan casually has a chat with the Player Character on their talent as a trainer before chewing out the grunts on their rude behavior and fashion sense.
There's a house in one of the routes with nothing but a man and many Pikachu inside (the "Pikachu Fan Club"). He claims he wants to challenge the League with a team consisting entirely of different Pikachu. You're probably seeing his entire team at that moment. Then you try talking with every Pikachu just because... It turns out one of them is
actually a Poké Kid in disguise, a kid trainer who dresses like a Pikachu. Who immediately challenges you, like usual. And guess what her team consists of?