I think there's a connection to be drawn between compulsive saving and ecological common sense.
While it hasn't reached pathological proportions, I, too, have the impulse to save those meat trays from the supermarket. Anyone who hasn't been programmed, as we American consumers are, to throw them out after a single use would be shocked at the idea. It's obvious that time, labor and natural resources went into the making of them. It's easy to imagine using them as plates, toys, craft implements, whatever. The family living in a cardboard shack in a Third World country might consider them a small treasure. So it goes against the grain simply to trash them.