On the Wikipedia page for Expedition Everest, it says the following:
So, I'm wondering, is it a better pre-show experience to go standby to see all the themeing? Or does it not make a difference?
As riders wind their way through the attraction's richly detailed standby queue, half of which is climate controlled, the legend of the yeti is communicated vividly through a mandir, a kind of Himalayan shrine to the yeti, and a makeshift museum that documents yeti sightings, its significance in Himalayan cultures and a so-called "lost" expedition that ran afoul of the creature many years before (1982). The shorter FASTPASS queue contains a similar but abbreviated storyline. The queues merge in the enclosed train station behind the loading area.