Suppose you went over to the dark side because they had cookies. You have your choice to join whichever evil Team you like. Which would it be, and why?

Hmm.  Well, Team Plasma are kind of Ghetsis’ silly brainwashed minions, Teams Aqua and Magma are almost entirely built around a stunning failure to appreciate the basic principles of ecology, and Team Galactic go a little too far for my tastes with their plan to, y’know, destroy the universe, so I suppose I’m going to have to stick to the basics and go with Team Rocket.  They have a sensible goal (money and power, in whatever quantities are achievable), they have no deluded master scheme that would threaten to derail their other plans and/or wipe out modern civilisation, they have a sensible command structure and effective recruiting strategies, and although they lack Team Galactic’s technological supremacy, they’ve still shown they can pull out some fairly impressive scientific expertise when the need arises.  Besides, none of the other teams have an awesome motto.