In any form of entertainment, boredom is a show stopper. We’ve all read boring books or seen unwatchable movies. They have unnecessary and unenjoyable scenes that could be put to much better use.
The same is true in gaming, perhaps to a larger degree due to the lack of editing in the course of a gaming session.
If I have to trudge through three hours of trite exposition (which is mostly irrelevant anyways) just to get to the half hour of interesting decisions and conflict, then it just isn’t worth it for me.