I just get frustrated seeing it, especially from the backs of peoples properties. It looks awful. I'm not talking about a few cans or whatever, I'm talking mattresses, white goods, cupboards, clothes, and even kid's toys.
I understand NR don't have the resources to clean it all, and I think I acknowledged that in my OP.
As for litter picks, yes I do get involved. I proactively clear litter in my area and have joined many a litter pick locally. I've even been in the local paper for it. Nice to see you do too, good work.