What is horrible, addictive, tempting, and ultimately leads to more misery?
If you don’t know what spoilers are, well, let’s just say they’re evil. They’re little hints – or not-so-little hints – about what will happen next in a movie, TV show, book, etc.
And even if someone is “okay with” spoilers, you should not give them any because they aren’t. They just don’t know they aren’t. You never know what could be the thing that completely ruins the movie or episode or series for them. You never know which tidbit of information will be the highlight of their experience, and if you give it to them ahead of time, it robs them of that enjoyment.
Especially if they have to wait to see the thing and are desperate for any information at all. When that happens, people aren’t nearly as careful or selective as they usually are, and often end up ruining even more than they would usually allow themselves to have ruined.