I now NEVER watch any trailers at all. I watched Terminator Genisys and while it wasn't a brilliant movie I did gasp a little at the reveal part way through the movie.

I asked my brother what his reaction was and he said he already knew going in as the trailer had revealed it.

I don't get the point of trailers any more. Most of them just show you the whole movie in 2 minutes.

Saying that, probably the best trailer of recent times was for one of the Godzilla films, which actually gave away very little and just gave you enough of a vibe to make you want to watch it.