When the last book in the Divergent Trilogy was released I stayed off tumblr and twitter just in case. The book was not ruined by the internets though but by a co-worker. I was minding my own business in the kitchen when a co-worker told me her daughter was upset by the end of the book because INSERT MASSIVE SPOILER THAT MADE ME NOT EVER WANT TO FINISH THIS SERIES. I couldn't stop her, it was early in the morning and my brain and mouth could not work together fast enough.
I still have not read Allegiant and I probably won't see the last two movies until I read the book (because of course they're splitting it into two movies to make more cash money). It's not just because I know of something huge that happens it's also because I'm really pissed at what happens. Damn you Veronica Roth.
I'll probably read the book eventually just to finish off the series but it just won't be the same.
Let's not forget one of the biggest spoilers of all time. I somehow managed to avoid having Harry Potter and the Half-Blood Prince spoiled.