1/3 of people can function okay with persistent poor quality sleep. 1/3 of people can survive but are very grumpy with persistent poor quality sleep. 1/3 of peo

1/3 of people can function okay with persistent poor quality sleep. 1/3 of people can survive but are very grumpy with persistent poor quality sleep. 1/3 of people suffer catastrophic consequences with persistent poor quality sleep. Apparently this distribution is completely random, and usually only manifests itself in situations like having a kid, etc.