Mine is Lost Highway. It’s one of the most amazing pieces of media I’ve ever experienced. It’s dark, surreal, and I still don’t know what it’s about for sure. I have my own interpretation, as do many others. Who’s right? We’ll never know. The film is a fucking trip. I highly recommend.
Gotta be The Matrix (1999). It blew my mind with the action when I saw it as a teenager, it continued blowing my mind with the philosophical and existential ideas when I started understanding those as an adult, and now it’s the ultimate comfort watch for me.
The two sequels have a special place in my heart too.