I don't believe that a constant level of happiness can be achieved - things cannot always be good and dandy. Obstacles can form at the most unexpected times and should be faced... Which is why I value izuon (e-zoon) so much. In Hebrew it means balance. It's something that I've always valued in my own life - a state of harmony.
And yes I could just call it balance but I think the word izuon has a much nicer ring to it :P