Whenever I construct a plot-arc that ends in a death, or even a tragedy, this is the sort of reaction that I hope I'm able to create. It's a hard balance (as all aspects of writing appear to be) where you need to create the drama and the power of a scene enough so that it reverberates into the reader, but at the same time, it doesn't leave them stunned and unable to think rationally (unless you're writing a book that intends to melt brains. If so, four for you.)
The "I get it, but I don't like it" reaction seems to come in two stages that need equal devotion. The first is the blow, the sudden realisation of what has happened (example: *hunky hero gasps, freezes, falls to the floor, lies still*). That's an awful example really and I hope nobody literally believes that to be the way to kill a protagonist. What it does demonstrate however is how the actions flow and the reader's mind along with it. Usually, the death is at the end of a chapter. When this has happened to me, when a character that I have emotionally invested in (as a reader, I stress. The writer angle comes later) meets their end, I have just - sat. So still, mouth agape, feeling as if the world has fallen out of rhythm with me for a split second, and then it resumes and I have to make the decision to read on again, even if I'm about to become a blubbery mess (Red Wedding...I need say no more.)
The "I get it" part always seems much trickier to me. When it comes to this, it's all about structure and approach to me. A reader thinks fast, sometimes very fast, especially when under pressure (they are a unique species...), say, when their whole existence is crumbling before them because their favourite character was struck down in their prime. The recovery stage is what contributes to the overall opinion of the story, and whether they enjoyed it overall. As I'll talk about in another chapter, there has to be a reason, and it can't be "I felt like it - they were boring me - I was having a bad day and I took it out on them". I wouldn't be satisfied by it as a reader (in fact I'd bring the thunder if I thought that was the only reason) so I'm not satisfied to do it as a writer.
Foreshadowing exists in a heck of a lot of books, because it can be one of the most subtle yet effective tools in a writer's arsenal. A reader has an idea something is going to happen, but nothing more. They think it might happen, but they pray it won't, and when it does, through tear filled eyes they whisper "I knew it." Foreshadowing also helps with the "I get it" part of a reader's reaction. Whilst they start to become suspicious that something will happen, their brain whirs away about why it might happen, how it might happen, and then - you guessed it - why it's okay for it to happen.
I've always believed that characters should be honoured. Reactions 2 and 3 are how I think this kind-of-sort-of fails to happen in some books, and why I tend not to like them as much afterwards. For now, I'll say this. When I was younger (because, you know, at 17 I'm reaching the end of my days...) I thought that readers were stupid. Even though I was one myself, I was a "special" reader, and all the others around me wouldn't understand my reasoning, and they didn't need to. I've changed now, I swear. What I see now is that readers are very free-thinking and intuitive. They will figure out why you've done something quickly, and so you'd better have a good reason.
When I imagine growing up and being published and going to a panel after the release of my new book (in which, of course, a beloved character popped their clogs), I always imagine my fans as being able to understand why I did something. They can jab at me all I want in good fun, and I can jab back and tease them by saying "he annoyed me so I impaled him on a chandelier. Take that, suckers!" But at the end of the day, they know, and I know, that there was a logical sequence of reasons and events which led up to this, and so even though they don't like it, they still get it.
And that's all I'd ever want.