Actually, flies love vinegar. It smells like rotting flesh, which is a great place to go lay eggs.

This unintuitive fact matches the truth that being rude to people is an important part of the process of personal growth. Getting people to change takes a carrot AND a stick. When they do change, they'll remember the carrot more easily. But the stick is important too. You can see this politically with the fact that the government likes to praise MLK for his nonviolent methods, but Malcolm X is the one who got Reagan to pass gun control laws in California. MLK's movement was threatening because the politicians knew that if they didn't work with the nonviolent protesters, those protesters would join movements like the Black Panthers. Likewise, rude leftists encourage people to be more open to listening to the polite leftists in their lives. The rude ones raise the stakes.