I love watching movies or television shows that always have twists and turns all the way to the ending. I also love re-watching these movies and television shows and seeing if I can see how the ending came to happen, often you'll be surprised (if it has been done well) at how many little details there are that screams at the viewer about what's going to happen. Sometimes it lies in an off-the-cuff remark that one of the characters make, to a photo that's hanging on the wall.
If you can't tell by the picture at the top, I just finished watching the season 5 finale of Supernatural and it was intriguing watching all the little clues placed throughout the episode (not to mention all the episodes leading up to the finale). By the way, I absolutely loved it... you can give me an angsty Sam over a brooding vampire any day (sorry Spike and Damon, my mind's made up).
Foreshadowing is the greatest tool that any writer, whether it's for visual media or in books, can use. One, it shows the reader/viewer that some thought has been given to the events that are unfolding, and two, it won't make the ending seem too sudden and drastic that the reader/viewer won't believe what's happening.
For foreshadowing to be effective, the writer cannot make the little breadcrumbs that's dropped throughout the pages too noticeable. If it is a glaring neon sign that screams "Pay attention here, this is important" then the reader might think that the author is treating them like an idiot. If there is no foreshadowing and suddenly you've got a twist at the end then the reader might think that the ending is unbelievable and that no way did it even indicate that the "buttler did it".
I absolutely adore stories that have me guessing till the very end. I often find myself flipping back through the pages to find the clues that have been thrown into the story to identify where the twist occurred and what caused it.
So, do you like stories that shows foreshadowing has been done? And, in your stories, do you try and foreshadow the events that are going to take place?