So I'm finding myself more than a little peeved with a trope I've been seeing with increasing frequency in recent YA novels, particularly of the paranormal/sci-fi/thriller set. That is, when the MC is in the dark about something and the mysterious ally/love interest/rescuer has all the answers but refuses to divulge them.

The most recent instance was a book where the love interest just kept saying trust me, now's not the time, can't tell you yet, every time the MC presses him for answers. And of course, shit happens that could easily have been avoided if the MC had been in the know.

But here's where books lose me. It's one thing if you genuinely have a reason the MC can't be told information yet. But when the answers are finally need to also reveal WHY those answers couldn't have been given a hundred pages sooner. Don't just gloss over that question and let it drop off the page, hoping readers won't notice. Because that's (IMO) the difference between a coherent plot with a plausible mystery, and just milking the MC's ignorance for all its worth, and not letting her know things that would otherwise ruin the shiny plot twist you have coming.

Anyone else see this in books a lot? Where do you draw the line as to when it makes sense to keep the MC in the dark vs where it feels like the author's just sacrificing logic for the sake of keeping a mystery going longer?