Ecclesiastes hands out more verbal beat-downs—this time to fools. Fools wreck everything with their follies—just like a couple flies can ruin a nice pot of ointment. (Like, cover your ointment pot, Koheleth—Saran Wrap, anybody?)
Yet, despite how destructive they are, fools and folly get into positions of power. (You should still listen to the king, though.) Ecclesiastes sees how often people who should be princes are slaves, and people who should be slaves are princes.
Next, Ecclesiastes sings a little hymn about how, whatever you try to do in life, it can backfire and injure or kill you: "Whoever digs a pit will fall into it" (10:8). The big take-away here is that you should be prepared for whatever you're undertaking—like, if you're a snake-charmer, you should know how to charm snakes before you start messing with them. (Makes sense to us.)
Talk is Cheap
The Preacher attacks fools again, saying that they just talk on and on, but it never does anything and eventually leads to destruction and madness. They need to just chill out. Calm down.
It's a good thing and a blessing to have a decent king in power. But even if you don't, don't even think anything negative about the king. A bird might tell someone, and then it's all over for you… because birds are telepathic, apparently.