Top Tier Movies But Actually They Are B-Movies At Heart

I mean, c'mon, they are surfers who rob banks, that feels like a solid set-up for a cheesy B-Movie popcorn flick, not the 100% adrenaline fueled action movie with philosophical and faintly political undertones staring one of the most beautiful casts ever put on screen.

What other top tier movies, at their heart, are just schlocky b-movies punching above their weight?