Anyone who is arrogant about his extreme "green practices" and imposes his values on everyone all the time. He usually thinks of himself as open-minded and non-judgmental, when in reality, he is often the most judgmental one in the room. This person will often bring up global warming or recycling at inappropriate times and gets offended when others don't agree with everything he says.
Steve needs to lighten up with the environ-elitist behavior. Last week after his grandpa's funeral, he yelled at his grandmother for not buying eco-friendly toilet paper.