Like Gloria, I am a crier. I have my own movies that make me cry, even after the 25th viewing, and always in the same places. I don't get as teary-eyed when reading books--mostly because I prefer to read mysteries--but there have been one or two books that I've thrown across the room, because I became so upset over what I'd read. And I will admit that I cry when most of the characters are killed in the Harry Potter books, including Professor Snape . . . even after several readings.
Since I too, am a sentimental person, why do I enjoy writing about murder? I think I've mentioned before that I think writers are in tune with all the human emotions; even the "uglier" ones. We need to be so attuned, in order to write believable characters that people will enjoy reading for 200 plus pages.
Take any horrible tragedy that you read about in the daily papers, and we can write it however we want, twisting certain plot points, and introducing characters to bring a somewhat happy ending to something that might otherwise end in more tragedy. Some murder cases never get solved, because there aren't enough clues to lead the cops to the perpetrator(s). But a mystery writer can take pen in hand and write the story differently, finding (read "creating") the one piece of evidence that breaks the case wide open.
The other cool thing that comes from writing mysteries (for me, anyway), is that you get to wow all your friends with how quickly you can solve a mystery. I can't tell you how many times I've had people bet me that I wouldn't be able to figure out "who done it," only to be frustrated later when I point out the culprit before the movie (or book) is half over.
Now's your chance to tell us what movie (or book) you were told you'd never "guess," that you actually solved quickly. Please don't give away the ending (for those of us who may not have seen/read the mystery), but definitely tell us the title.