What is the most influential movie on your creativity?

For those who are into the creative arts - even if it’s daydreaming - what has been the most influential move you have ever seen that changed you? Which one changed the way you saw storytelling, cinematography, drama, etc. and you ultimately put it into your own creative work? Could be a foundational one (Alfred Hitchcock) or fairly modern one (tenet). Doesn’t have to be something profound, could be something as little as “James Gunn taught me how to use B-characters in GOTG or Suicide Squad”.