I ask myself that question from time to time and I find a disturbing trend towards intolerance whenever I'm feeling poor in some area.
When I think of the "poor in spirit", I don't think happy, I think instead of envy and intolerance. Sure those who BECOME happy overcome their "poor-in-spirit-ness by focusing on self improvement in those areas of felt deficit, however I imagine the unhealthy may become more intolerant, envious and controlling.
Anyway, just a brain-fart.