And when they were wrong they were very upset with me (lol!)

That's how you know you're writing lmao! Guess this isn't something that's exclusive to professional writers.

lol! Yeah, I guess the pros must have taken it from us, huh?

It hasn't happened on fanfiction.net, given that the only thing I've written there was a oneshot, but it has happened on other sites. I haven't had anyone being upset because they guessed wrong, though - or no one admitted to being upset, anyway.

That makes sense; I feel like one shots are harder to make predictions for.

^People are also less likely to comment about predictions they made in the middle of the story/chapter, and whether or not they were proved right by the end, than they are to make predictions based on endings and cliffhangers.

I guess that might depend on the fandom. Speaking on my personal experiences alone a lot of my reviewers like to make theories and predictions and say stuff like, 'but that's just a theory, can't wait to see what you'll do,' I really like those kinds because they don't put pressure on authors but it's neat to see their takes on the story.

^But they tend to make those comments before they've read the next chapter and found out if their guess was right, don't they? That's what I meant. In the past I was often asking my readers for guesses of future events - that was one of the best ways of getting feedback.