Describe a game experience that changed how you play.
Totally not a question, but we've gone down this route before . . . 😉
Now, to get a bit more serious about the question. I think the first experience that fits the description that springs to mind is when I first started running Marvel Heroic Roleplaying.
I think it is safe to say that most of the games I had played up to that time were designed to emulate living in a given genre, rather than the genre itself. The rules were used to model the world, and you were encouraged to think and make decisions based on how you would if you were a person living in that world
Marvel Heroic Roleplaying encouraged thinking about the narrative of comics. Not acting the way you would if you had Peter Parker's powers, but thinking of how Spider-Man would react in a given scene to make that scene feel the way it did in the comics in which the character has been featured.
You were still playing a role, and making decisions for the character, but you were doing so in a manner that was much more conscious of the genre and its tropes, and the game rewarded you for playing to the tropes.
Not only did I really enjoy running Marvel Heroic, but it was the first time that I ran a game online for people I had not met. Running Marvel Heroic for the first time got me back into running games at conventions, because I had a rekindled urge to play with new people that I had never met, and it helped me to better understand more narrative games, like Fate and Powered by the Apocalypse games.
And it all goes back to that first session of Breakout that I ran all those years ago.