funny options, true dat! In my case it usually loops, like dream in a dream (inception, lol). But still it's mostly uncontrollable, you may think you are in charge while you're actually not.
The directed dream usually ends when you come close to your desired destination because you become too excited and too conscious about it and it doesn't flow naturally as an uncontrolled dream would (though too much excitement almost always awakes you in any case)
Yes, but this is the exact moment when you start lucid dreaming. If you practice, you can actually control your excitement and, consequently, your dreams as well. After a few times, you will already start the dreams controlling them. Nothing more awesome than just taking off in flight, or going to other planets, or finding any person you want and doing whatever you want with them.
There are a few things that can be done to help you lucid dream. If you want to know, we can talk in more detail. I suppose PM would be best, to not fill this topic with off-topic discussions.