Here's some torpedoes of truth vis a vis Show of Life: The songs a big's arena rock statement of form. Phish now defines and exemplifies arena rock. Therefore, Show of Life is perfectly suited to this period and a more than welcome and appropriate encore selection.

And, it was written with the Dude of Life over an iPhone chat. If that's not in the spontaneous improvisational spirit of Phish (although the text of the song doesn't allow for improv like we desire), then I don't know what is.