Stan Lee rose through the ranks of Marvel Comics (then known as Timely Comics) starting as a lowly assistant before becoming a writer, editor and ulimately becoming the driving force behind some of the most well known and beloved comic characters of all-time.
Superheroes were always seen as untouchable and Stan successfully broke that mould by making his characters seem more human by giving them obvious character flaws, making them younger and shattering the idea that all heroes were untouchable.
He (sometimes in collaboration with others) created the Fantastic Four, the Incredible Hulk, Thor, Spider-Man, Iron Man, the X-Men, Daredevil, The Avengers and Dr. Strange. It's hard to imagine that the comic industry would exist in the way it does today - with so many associated TV shows and movies - were in not for the way Stan Lee completely overhauled the way things worked.
Thanks for the memories, Stan. Excelsior!