Dreams for me are pretty cool things. I have never had a dream that I recall being upset about, although I'm sure it happened often enough when I was young. I remember very few things from when I was young.
But my dreams can be quite weird, as I'm sure everyone's can be. I've had dreams that other people would find upsetting I'm sure of it. My weirdest ones are often involve a theme of either being hunted or hunting someone. Not that that is weird in and of itself, but the combination of elements in those dreams in particular lead itself to something that seems or feels sinister when I recall the dream in the morning.
Last night was the first time ever that anyone in my dreams died. When I woke up, I didn't feel that upset about it, but I've been brooding on it through the day and I'm no longer sure how I feel about it.