If cleanliness is next to godliness, dirtiness is next door to a happy, grass-stained kid. And, depending on the contents of our soap, when we go dirty it makes a happy orangutan, too. It's not that orangutans have a deviant fondness for stanky humans, but rather that farming palm oil - used in food and products like soap - encroaches on their ecosystems. Palm oil plantations have led to conflict with orangutans in Borneo, by shrinking orangutan habitat as well as farmers directly killing the apes.
5. All the sweet things (ekilby/Flickr /CC BY 2.0)