Reliability is a key issue for writers. We rely on being able to type, being able to blog, on the internet and so on. (Back up, back up, back up all work as regularly as possible. I learnt my lesson the hard way there after a power cut one night. I lost an evening's work but got it back thanks to recalling most of it and starting again. Now I back up every 15 minutes or so).
Reliability should be a key issue for characters. Are they themselves reliable? Are they right to trust other characters in the story? What happens when they are let down or betrayed? Do they seek vengeance or simply swear never to trust anyone again (and what are the consequences of that? Could be significant).
A reader has to trust that the author knows what they are doing and will follow through on the plot and characters so ensure you do!