I feel, just like movie trailers, that these 'previews' ruin the articles by giving away too much. Why would you read the article if you've just read the cliff

I feel, just like movie trailers, that these 'previews' ruin the articles by giving away too much. Why would you read the article if you've just read the cliff notes? Previews should entice, not give away too much. Movie trailers look awesome because it's the best the film has to offer, making the full length feature look pale in comparison, which is why I try to avoid them at all cost.