I analyze the plot and think of all the different possible outcomes and if those outcomes are wrong nobody cares but if one of my thoughts were correct then your movie is predictable and therefore bad.
I may be missing out on key subtext like themes or symbolism but I can't miss a chance to virtue signal my own intelligence which is higher than that of the filmmaker.
Maybe I shouldn't go into a movie with a "you better impress me" attitude while constantly trying to predict what's next because maybe having a negative mentality might affect my viewing experience negatively or maybe amusement parks are more for me but I still want to have an opinion even on things I don't understand or care about so I treat art like a math test rather than an empathy building endeavor.
Predictability is a valid criticism for a movie but every movie that's found a large audience has been called predictable by someone but when I say it it's true because I'm smart or perhaps all movies are predictable especially after I've seen them.
I've never made a movie but if I did you wouldn't be able to predict exactly how ****** it would be.