Speechless

I'm pretty verbose. It takes a lot to leave me speechless. I went to the library yesterday to get some books on how traffic and zoning effect the environment and health. The girl behind the counter commented that she liked my shirt (it is a home made iron-on that says, "what high gas prices" and has a picture of a gas pump and a bicycle). I said thanks. When the girl was done scanning and stamping the books she asked if I wanted a bag. I responded that it would be sort of silly to get a bag to check out a bunch of books on how to protect the environment. She said, "It's OK, the bags are plastic. It's not like they're paper and we had to cut down a tree for it." I don't know what my facial expression said, but there was a lot going through my mind. I was perplexed and completely unable to formulate a sentence, so I left... speechless.

Trees are renewable, plastic is a petroleum product and therefore not renewable. Paper biodegrades, plastic doesn't. Plastic grocery bags have recently been outlawed in San Francisco because of their environmental impact. Do people really think that plastic is a good thing? How do you respond to a question like that?