It is because you believe your body and you to be the same thing. You are where your thoughts, daydreams, dreams, ... essence is.
You have already had many implicit obe experiences.... but while you 'try' to have an explicit experience, you allow your mind to paint you an illusion that you are attached to your body. If you can't keep your mind quiet... try instead to think of yourself as a spirit enclosed in a vesel, i.e. your body. Then stop thinking about getting out... simply think of being somewhere else or looking at your body... and it will be so. When you project yourself somewhere... anywhere... you will soon come to see that the projection is not a conjuration of your mind, but is instead real, i.e. that you have already left your body and is looking at something in realtime.
You have already had many implicit obe experiences.... but while you 'try' to have an explicit experience, you allow your mind to paint you an illusion that you are attached to your body. If you can't keep your mind quiet... try instead to think of yourself as a spirit enclosed in a vesel, i.e. your body. Then stop thinking about getting out... simply think of being somewhere else or looking at your body... and it will be so. When you project yourself somewhere... anywhere... you will soon come to see that the projection is not a conjuration of your mind, but is instead real, i.e. that you have already left your body and is looking at something in realtime.