The joke is that the audio on the post was "In The End" by Linkin Park

Here's the thing. Due to executive meddling, the series was forced to end early. So unlike shows that got cancelled out of the blue, here they said wrap it up ASAP. There were loads of unfinished plot lines that were left unfinished because of this, and the series finale was rushed at best. Hartman still had stories to tell, they just didn't let him.