the 4th dimension (I'm assuming that's what I'm experiencing when i astral project) can be a very foreign and sometimes scary place, because you become conscious creation, what you think just happens, so if you're scared, or mad, or sad, your emotion will manifest physically around you and have the physical aspects of how that emotion feels towards you,you can literally create your own hell, or nirvana, depending entirely on your ability to control your thoughts and emotions.