A rewarding interview with one of the writers of the 'Alien' prequel, 'Prometheus', Jon Spaihts:
His bit about the central predicament defining the protagonist is obvious, yet insightful.
And he goes on about making narratives compeling:
"There are three motives of story that matter: having something that you hope for, having something that you fear, or having a burning question that you need answered. Any one of them is sufficient. If you can have more than one of them running at one time, or all three—you can be afraid of one thing and fearful of another and desperate to understand some mystery that's been dangled in front of you, then you are maximally engaged, all three motors running."