Why'd you kill him?

Hmmm... gotta think how to write this post without spoiling my own story.

A little while ago, I was writing at night, and I finished a scene where someone dies.
Mom was reading the next room over, so I went over to bug her a bit, by saying "boo hoo, this guy died." I was mainly being dramatic, though I was sad too.
And her response was "Why'd you kill him?"
Which kind of stumped me for a bit. Because I started to think, "why do they kill characters?"

Obviously, this question is different for every creator. Sometimes a character is killed for absolutely no good reason.
Sometimes a writer ends up killing everyone... (Les Miserables, Wolfs Rain, ex).

Sometimes no character dies. The writer goes out of his way to bring a character back from eery tragedy... sometimes if they've already died.
Some characters die in order to trigger action in a story.
Or a death can make the stakes of the story much higher.
And as some people will say, certain characters have to die because they're just too awesome to live. ...Well, as long as it doesn't happen every single time you have an awesome character. --_-- Plenty of them deserve to live.

But mainly I was stumped by Mom's question because I wondered why I killed some of my characters. There's a couple that I've written already. And there's a couple (especially one) significant one that I have planned (for a character I'm extremely attached to. TT^TT ).
And I can't think of a clear reason why some of these characters have died.
The most obvious one is the final one I mentioned - it shows that the danger in the story is real. For example, in Katani's story, there's a big fight at the end. And a lot of people get hurt. If all of the characters we follow somehow miraculously escape unharmed... well, was it really that dangerous? Doesn't see like it.
This is actually one scene I thought about a lot. It seemed that someone needed to die. But I just didn't think it would work for any of the main group. So I settled on a minor character. I probably need to give him more screen time. If I have to kill him, it should at least hurt.... otherwise he's dying for no reason. TT^TT I'm soooorrrry I have to kill you. TT^TT
So, yeah. that's one I need to work on.
On some of my much older stories, people died. I don't particularly think that's worth discussing. But "someone" does die in my Ashes story. Except while I am attached to the character, I'm not sure anyone else would be... So that's another thing to work on. --_-- Also, I should find a reason for why he has to die.

What do you guys think about killing a character? What are good reasons? Or bad ones?
(I know no one ever uses these prompts, but I like writing them. And maybe someone will use one some time. O___O )


Hmmm... I should make a list of some of the most painful deaths. I'll start working on that. And sobbing all the while. TT^TT