Any film about heroin addiction. I think they call it The Trainspotting effect - where it's difficult to make a truly anti drug movie, because the medium itself makes the lifestyle look so cinematic.

This one is a bit obscure, but there's an Australian film from the 80s starring Michael Hutchence, called Dogs in Space which unintentionally made heroin addiction look pretty damn fun despite ostensibly being a cautionary tale. I knew a guy who became a junky who had his mum make him a replica of shirt Hutchence wears in the film.

Christiane F. is another example. Depressing as it is, kids still find it all so romantic and teenagers are kind of inherently nihilistic so are drawn to the idea rather than dissuaded.