Superman the Musical

Why is it when some shows end it's a happy ending and others it's a sad one? For example Superman the musical. I can't wait for it to be over. It's not that i hate the people in the cast or crew or that we don't have fun i just want it over. Where like other shows such as peter pan this summer was really fun and i didn't want it to end. I think that the reason that some shows just need to end is because there is never anything intresting that happens in the show and it has no real meaning anymore to you becides that you get money. Where there are other shows that yes you get money for working them but it's also fun and you have more then one job to do for the show or the the one job you have is chellenging. That is why i believe some shows don't want to end and others just need to be finished and over with.