Tell them that Republicans are the root of evil because they like to get rid of trees, not provide enough funding for the social services programs and or quality of life programs, such as cutting park and library budgets, they like to ruin the environment, and they'll do anything to get another vote.
Then tell them to take a look around while they drive in a car with their parents, all of the ugly signs blighting the public streets, bad traffic, lack of sidewalks, and ugly subdivisions are because politicians do not listen to planners - therefore our world is not as pretty as it could be.
People who live in gated communities are snobs, so don't be friends with them.
(Well at least that has been my experience.)
Positive things to talk about: (Brainwashing early is so great!)
Planners create the world; we make it a better place.
Geography is all around us, so pay attention to your teachers.
Historic/archaeological preservation are keys to our past, so pay attention to your history teachers.
We get to play with cool computer programs like GIS.