Be able to stop loading up a project.
I would bet we’ve all accidentally opened a wrong version of a large project that we didn’t mean to, for instance, and then have to sit there while it loads up, then quit and re-load the correct project (which is especially fun when clients are in the room waiting – when you have a video game score with huge amounts of different large cues and versions, it’s not hard to imagine that this can quite easily happen).