Spoilers are such a touchy subject.
I have a bunch of friends who watch the show Game of Thrones but haven't read the books, and back when the show was way behind the books, I couldn't talk to them about anything because they didn't want to know. When a fellow book reader accidentally let slip that a certain...important character...dies, the TV show watchers were DEVASTATED.
"YOU SPOILED IT! NOW HOW CAN WE WATCH THE SHOW? WE WON'T BE SURPRISED OR DEVASTATED OR ANYTHING AND LIFE WILL JUST SUCK."
Well...I might be in the minority camp here, but I don't mind spoilers.
Don't get me wrong, I'm not about to go looking for how things end. I'm not one of those people who flips to the last page of a book to see how it ends before I finish. What I mean is that if for some reason I accidentally find out some giant plot twist or Deep Dark Secret, I'm okay with it. In the words of Markus Zusak in The Book Thief.
"I know what happens and so do you. It's the machinations that wheel us there that aggravate, perplex, interest, and astound me. There are many things to think of. There is much story.”
Sometimes it's nice to get all the plot aha moments out of the way because you can pick up on so much more foreshadowing and subtlety you might have missed if you didn't know what was coming. I've found that particularly with the Mistborn series and Code Name Verity, I've loved the books so much more the second time I read them because I was able to better pick up on all those subtleties.
Yes, part of the fun of reading a book or watching a TV show is the anticipation of what comes next, and it sucks when you don't have that shock value. But if you think about it, don't you still have that anticipation when you know what's coming? I know my heart starts beating really fast during the stampede scene every time I watch The Lion King even though I've seen the movie so many times and I know what's going to happen. It's like watching the inevitable unfold before your eyes and knowing what is going to happen doesn't make it any less painful or emotional (if anything, I'm more emotional on rereads and re-watches).
I'm not advocating that you go around spoiling things for everyone, but if something does get spoiled for you, I wouldn't blame you if you needed to take a minute to scream raise your fist at the unfairness of it all. Once you get over it though, think about all the possibilities you've opened up and enjoy the ride!