Or maybe people have different expectations of what they want to get out of a movie, book, etc. during the first exposure compared to repeated exposure.
To be entirely forthcoming, on very rare occasions, I have quit reading a book or watching a series because I have looked up future events within the story and disagreed with them or disliked them so entirely that I am no longer willing to continue. However, I can only remember this happening 2 or 3 times in my entire life, and I usually "quit" because I just so vehemently disagree with the ultimate outcome that I am not willing to continue to emotionally invest in the story if that is where it's going. That being said, it should also be considered that I am a self-admitted watcher of comedies over dramas because I prefer to invest my entertainment time in that which amuses me over that which distresses and/or saddens me. I do not think this is an unreasonable choice but I think the fact that it is a conscious choice educates my feelings re: spoilers and ultimate outcomes. Once, a boyfriend took me to go see Selma in theaters. I think Selma was a great and important film. However, after seeing it, I was angry at him. Why? Because I did not go on a date with a boy I liked in order to spend the night crying. (My anger may have been somewhat misplaced but the point stands.)