Yeah...pretty old, resurrected thread.
I've found a lot of the stuff mentioned throughout the thread. But the one thing that I find way too much of (well, not find but 'see' too much of cause I don't keep it) is improperly disposed-of, discarded, bagged dog poop. EVERYWHERE! Every time I'm out. Not just on rides, but when I'm running too. In the streets, roads, sidewalks, parks, beach, and even in the woods along designated hiker/jogger trails. People...if you're too lazy to carry your dog's poop to properly dispose of it...just leave the exposed poop and don't bag it. I think it's less damaging to our environment.
Dan