Unclear?

Now I am not sure who is unclear on the concept, but...  Last Saturday on the way to dinner in the City and we pulled up behind a Prius.  A very ecological car right?  You care about the environment, right?  Always a good thing.  Then comes the unclear part.  Tied to the top of the car in a big plastic bag was a big old Christmas tree?  You will drive a car that gets a billion miles to the gallon to help the environment, but you will cut down a tree that took years to grow so you can put it in your living room for a couple of weeks, not to mention the plastic bag which will be in a landfill for who knows how many years.