Nothing drove my adoption of prime video faster then the auto play on Netflix. To their credit I contacted them asking if there was a way to turn it off and at least spoke with a friendly person about how awful it made the experience.
Personally I've enjoyed the feature.
I find it annoying on youtube though, for some reason.
Edit: Oh, wait, are you talking about autoplaying preview trailers or autoplaying the next episode? I like the next episode feature, autoplaying trailers are annoying.
Prime doesn't have the bizarre, useless, space-wasting auto-expanding selections like Netflix though.
Netflix stream selection UX is so infuriatingly atrocious.
I really dislike the modern Netflix UI. I miss the old Netflix, where you could rate your shows with stars, it did a good job of actually suggesting things, and didn't force you to make choices you didn't want to make.
And yes, since you ask, my TV’s mute button doesn’t do anything when speakers are connected via the optical cable (I suppose it sends some event and the optical -> analogue converter I use to hook the TV into my ancient sound system just doesn’t know how to handle it). But that isn’t Netflix’s fault.