I'm having trouble understanding the rationale behind the meaning of an American English phrase of which I just became aware. That phrase is:
You catch more flies with honey than you do with vinegar
From what I understand now, this phrase would indicate that You make more friends by being nice than by being rude. Please correct me if I'm wrong.
My confusion comes from the fact that no one catches flies in order to do anything nice to them (Well, I suppose some people do. But it's not common!). When I first read it, I actually thought the phrase meant You'll have more success luring people into a trap by being nice than by being rude. This didn't make much sense in context, though, which led me to ask around about the phrase.
Where does this phrase come from? More importantly, why does it have such a counter-intuitive meaning?