Reincarnating is like a giant jigsaw puzzle. Each time you reincarnate you put a few pieces in their proper place. Once the puzzle is complete, you see the entire picture and you understand this realm of existence. Then you can move on.
On the other hand, if you don't want to come back to this planet there are other places you can reincarnate, much easier places. Souls come to this planet because the learning curve is much shorter, albeit it's a harsher place. Pain equals learning.
If you hit rock bottom, start picking up rocks.