Like so many other readers, I am frustrated by interminable series that never end. I complain. Loudly. Publicly. In print (well, HTML). I do this because it’s the right thing to do. I may have a twinkling of a hope that some authors will wake up and conclude their series. But that hope is as long-lived as a firefly. Alas.
I do make an exception for works in which the destination is never the point, in which the goal is simply to enjoy the journey.