Dr. N: Earth is considered severe? S: Yes. On some worlds you must overcome physical discomforts— even suffering. Others lean toward mental contests. Earth has both. We get kudos for doing well on the hard worlds.
This paints a bleak picture. The good news is that suffering always have meaning and purpose. The bad news is, we are going to suffer through countless lives, basically we were created to suffer. Growth seems to come only through pain. What a drag.