Subtitles detract from the film to me. The only time I'm OK with it is if the film maker deems it necessary to convey the actors words/ thoughts to me. When we were sharing Netflix accounts, one of my sons would leave subtitles on, and I'd immediately turn them off, at the time I think it was during Peaky Blinders.
I've never thought about it like Kingkoopa6 describes above, but it really distracts me from "taking in" everything that's happening on the screen.
I actually like the previews, but sometimes, I think to myself, "that's 4 movies I will absolutely NOT be coming to the theater to watch." When our kids were little, they liked the previews, because typically the previews matched up genres with that which we were already there to watch. If we were there to see POTC, and you got 3 romcoms and a horror flick, yeah, they'd be saying, "This sucks!" but if it's the next Spiderman and a Christmas movie or something, yeah, they liked em.
Concessions are what they are. We typically would get the big bucket of popcorn and drinks for everyone. We smuggled in candy. No ragrets.