I reckon it's the level of consciousness of the individual. Steve has
blogs on this and I'm thinking of the concept from David Kawkins book, Power vs Force. basically what we're all describing is if you are over about the 200 mark, you are above fear, anger etc and are able to cope with challenges thrown at you. If you are under 200, you will buckle.
My 2c worth..
Joy to you (that's at 540 on the scale)
Hazel