Crisis in Morale: The Grass is Always Greener Syndrome

I've recently read about a study that concluded we all have a natural equilibrium level of happiness, that can be temporarily tipped for the better or worse, but we always gravitate back toward our natural happiness sweet spot.

I've also noticed that people, myself included, are grand optimists about the unknown. My personal happiness is strongly connected to the quantity and/or quality of opportunities I perceive I have in any situation. Which naturally leads me to be very happy at the beginning of things - friendships, jobs, etc. But that happiness fades as I learn many unknown areas that I thought might be doors to utopia are really just brick walls. As this occurs, my instinct is to jump the fence into the next pasture kicks in.

Is this just immaturity? Does a wiser person than me know that "opportunity is where you are" and that greener pastures are just an illusion? Does it matter at all if we all just end up at our equilibrium level of happiness anyway?

The point of all this that I have what many perceive to be a dream job that I think I want to leave. My job is really super fun about 1/5th of the time, however, most of the time I'm pretty bored, and occasionally (and seemingly more frequently) I'm really miserable. I'm getting the itch to move on to something else but is it stupid to leave? Its like the turning point on a game show when you have to decide to take your $100,000 and run or go for the $1 Million. I really want the million...