Thanks for the input - yes, agree that I am unhealthily obsessive about it. It seems like such a small thing though. We are a very low-waste household (one small grocery-sized bag every eight weeks or so); we freeze compostable waste and I bike a brown paper bag of it into work every week; we buy in bulk and use our own containers, etc. etc.
But ... the junk I find in the trash and recycling ... sigh. I should just avoid looking.
Re. the dentist, they are definitely at fault because they bag their own items and I was in the room when one of them came in to dump the bags into the recycling bin. One bag contained shredded paper - yay, fine - and the other two bags were medical waste: masks, latex gloves, bloody cotton and tissues, single use plastic cups, all mixed together. I only realized what was in them after she left the room.
We're DINKs with no kids and we'll be either donating our remains to science or getting planted in biodegradable eco-burial pods in about 25 years, so I ask myself why we should we care so much.
The thing is, most people are aware that we are ruining the planet, but few people take personal responsibility for their crap. They expect the GOVERNMENT to fix things, but then those same people turn around and complain about too many regulations, and they complain about extra taxes.