Check out the documentary Dive!, which will take you into the world of dumpster diving. It is all about re-using things that other people throw away.
We trash things others cannot even afford buying. You will be amazed by how much that actually is. Bin-diving wants to point out this waste of things; it has its own philosophy and is constantly in conflict with the law. (but how can re-using trash be against the law,especially if we talk about tons and tons of thrown-away food?). For more info on the topic check out Save Reno Dumpster Diving.
In times where countries like Somalia encounter the worst drought in decades and many people flee from hunger, how can we still throw away food?