Actually, I don't think I'm unreasonable at all, and am sure anyone who saw Blue Planet will agree.
We don't need disposable coffee cups, you can get reusable ones for around £1. When you're buying carrots or garlic in the supermarket, why are you taking a wee plastic bag to put it in? Plastic straws are also totally pointless - if you truly have some sort of condition which means you NEED a straw then get paper ones. 5p carriers should be banned - bags for life only.
In fact, other types of plastic should be taxed too. Christmas cracker gifts - mostly plastic and then chucked after an hour.