I'd say style or substance are really important and often over/under used which causes things to fall flat. If you've ever seen movies like Eternal Sunshine of the Spotless Mind, Donnie Darko, Brick, a lot of people liked those movies simply by how they were presented, despite how confusing they were to a lot of people, and even the people who understood them perfectly may have been turned off had they been presented differently

A movie that comes to mind right now is called Outlander. I'm not even sure how this movie got green-lighted for production. A space-man crash landing in viking times and having to team up with the vikings to help slay an alien that he accidentally brought with him. That kinda plot can easily fall flat on its face, and the first time I heard about it I figured it was going to be a ridiculous movie, considering how Hollywood works these days. But it was done extremely well. It took itself seriously and hit pretty much all the right chords, and presented a really well done "Grendel" type story

If you know what you're doing and how to present it, you can make garbage amazing. Style and substance are important. Just don't have too much of one or the other