A happy nurse makes a happy patient

A long time ago I read about a study that showed patients are most happy when the people taking care of them are happy. This is something I knew before I even entered RT School. 
The hospital I was first hired at had a meeting for all staff to attend, and basically what we were told was that a recent study showed that patients are happy when nurses are happy.  So the administrator at the meeting told us all we needed to "smile more."

I found this to be quite commical, because this administrator had obviously misenterpreted the study.  Patients aren't happier because unhappy nurses fake a smile, patients are happier because nurses are happier.  And, for the most part nurses are happier for the following reasons:

1. Good pay
2. Good benefits package
3. Low patient load
4. Low level of burnout
5. Empathetic, understanding boss
6. Happy home life
7. Good communication

Now obviously the hospital has no control over all these things, but it can at least do well with communication.  And it's obvious that nurses with a low stress load would be the happiest, so the hospital should make a gallant effort to have an appropriate nurse to patient ratio.