Team Magma and Aqua steal from a museum, and then two old people. Then they try to take control of a super-powered Pokemon, while ignoring the fact that too much land or too much water would KILL EVERYONE. I think Magma tried to make a volcano blow up, so I'll give them that.
Team Galactic, I forget what they did. Case and point. Something like trying to control the incarnate beings of space and time, I dunno. It's stupid.
I haven't really played much of Colosseum or XD, but those bad guys were pretty cool. Much better than Magma/Aqua and Galactic.
Now, Team Rocket. Their boss infiltrates the Pokemon League, becoming one of the Gym Leaders. They killed a mother Marowak for trying to protect her baby from being stolen. They did something at the Pokemon Tower that I forget. I dunno. They, quite literally, have a hostile takeover of Silph Co., the biggest company in Kanto. Team Rocket doesn't want to control a legendary Pokemon. They MAKE a legendary Pokemon. And, at the same time, clone a human (if you're going by the show).
Then they're disbanded, but it's by RED, so that doesn't make them less awesome. Three years later, they start cutting off the tails of Slowpoke to sell them. Cutting off. And they don't have a factory designed solely to cut off the tails. So they probably cut them off with knives. Then, they use radio waves to make Pokemon evolve. Having trouble evolving your Dragonair? Tune in to 99.5 and presto, insta-Dragonite. And a SHINY one, at that. Team Rocket's base in Mahogany needs the ELITE 4 CHAMPION to take them down. Then, they take over the Radio Tower, probably to transmit some radio wave to control every single Pokemon.
So yeah. My favorite is Team Galactic Rocket, as if you couldn't guess. I almost wouldn't mind having Giovanni as an evil dictator. You know, besides the Pokemon cruelty and all.
-PN