Why do "answers" never address the questions?

I can't find a straight answer to questions. Why do I have multiple libraries when I've never done anything to create them? Why does my iPhone synch fine one week and the next week tell me it's "synched to another library"? I have not done ANYTHING to create another library. All I want is a simple synching process. But iTunes seems to have a mind of its own and do whatever it feels like regardless of my input.