Comics had been a part of my childhood via Hulk and Batman annuals etcetera. When I was, maybe 15 or 16 a friend handed me a copy of Frank Miller's The Dark Knight Returns.
This was completely different to any comic book I had read previously. This was art. My school years were very literature focused and at home I devoured 2 to 3 books a week. I read a lot of Stephen King and Dean Koontz but some Dickens and Cervantes sneaked in from time to time.
This book, this comic, took concepts that my teenage self thought he'd grown out of (spandex suits and superpowers, escapism for kids, right?) and made them very real by mixing them with some very complex themes. Ageing, the cold war, power corrupting, the generation gap, societal breakdown. The lightbulb came on. Comics aren't just for little kids.
I was hooked. Frank Miller, Alan Moore, Warren Ellis, Neil Gaiman, Grant Morrison, all demonstrating to me that comics are art, comics are literature. Two decades later and I'm still going.