Or the styrofoam worm containers... that one bugs me a lot. It gives anglers a bad name, whereas the other garbage could've been left by anyone.
I usually bring back some amount of garbage each time I go out. Last time it was a dustpan and takeout styro from the Stave. Before that it was 5 half-empty Gatorade bottles, 4 beer cans, fishing crap, and an old sock from the Brunette (thankfully they left me a bag to carry it out in, especially that sock!). Last year I pulled a bunch of batteries from the banks of the Stave. Someone had driven out to dump them two feet from the water, along with a bunch of other electrical junk. Grrr....
EDIT: Yes, charge extra for takeout cups! And plastic grocery bags. It's just such a thoughtless waste of resources.