Has Michelle ever encountered a ghost, herself? Ever been spooked, human or animal? Or been in a place and got the absolute heeby jeebies? She describes it so well, particularly for me in Dark Matter, where in reality could she not face going? (for me it would be dense rain forest)
To frighten readers, a ghost in a story has to have an agenda, she suggests. I agree. The idea of there being an agenda...particularly motivated by rage is a terrifying idea.
'Ghosts' in 'real life' may not have any agenda, and are not necessarily frightening. Not in my own experience, except once. Startling, yes, for sure. Alarming but not terrifying, absent malice, but the once was enough and its ingredients were despair, fear, shame and rage.
Hers are frightening because the ghosts are as despairing as enraged, and not only unassuaged but unassuagable. It's too late. The idea of 'too late now' is almost more frightening than anything else. When I first read Dark Matter I thought to myself, if a devout prayer couldn't ease that soul, then what is it for? Put the Archbishop of Canterbury on a boat, stole, mitre, mittens and send him over to Gruhuken. Though a plain priest might do better.
Does Michelle now speak 'dog?' (wolf) Like dog whisperers do? I was late, learning about cats, eventually learned to yawn and blink at them. They do it back at you. Cat etiquette saying, I'm no threat.