It makes me wonder if we aren't using human waste properly.

I'm being serious.

We don't absorb all of the nutrients and calories that we consume, partly because we are overnourished (our bodies might spontaneously combust if we utilized every single calorie we ate), so there's plenty of leftovers in our feces. Does it ever get recycled for use in agriculture in "developed" nations? (I can't think of a word for that which isn't now a faux pas)