It should come as no surprise to you that a majority, if not most, of the objects and materials that we use daily have required that someone or something has expended effort and energy and time to make those objects and materials. Effort is expended not only in actually making those objects and materials, but also in purchasing them for home or for someone. I believe that our tendency to think of some things as "disposable" stems from who expends the effort in finally getting those objects and materials to you. It seems like the last exchange of resources (generally monetary) tells us to a great extent whether or not we would be okay with throwing something away.
I want to illustrate this tendency with the example of a plastic trinket. The hydrocarbons used in the plastic trinket were probably extracted from some oil field by several workers, then shipped or transported by several workers, then processed and made into the plastic trinket by several workers, then brought to a store by a driver, then stocked by a store employee. This trinket can finally be purchased by you for yourself or your family. On the other hand, you may purchase the trinket for someone else. If that person knows you, she might keep the trinket, at least for a while, recognising that your money (earned through hopefully "legitimate" ways) went into the trinket. There is a sentimentality that comes along with the trinket. If that person doesn't know you, she might not mind throwing it away if it is cluttering their lives. On the other hand, imagine yourself as the recipient of an object, say a plastic cup. You've chosen to use this plastic cup to drink water from, say during a talk or a seminar, or at a random fraternity party. Clearly, you have not worked for the cup. All you've done is pretty much shown up to the event, and there sat an unused plastic cup perfect for quenching your thirst. Now, I know people have a tendency to use "disposable" objects in their homes that they themselves have purchased, and have no qualms of throwing them away. I could of course go through the various permutations and combinations of scenarios, but that really isn't the point of this post. If you've sweat for something, you just won't feel as compelled to throw it away as compared to the case when someone else, especially someone unknown to you, has sweat for it.
We have the tendency to only think of immediacy - who was the last person that I associate this object with? We don't seem to think of everything done along the way by other people to make it possible to have the objects that surround us. These people are in no way different than you are. Their effort is every much as important to the object as is the last person's money. How might we better value these efforts? I guess this is the cause of most problems that face us - we only think of ourselves and our immediate ones in a world that is clearly a web of interactions.