I remember one day hearing my father downstairs laughing his ass off. Went down to see what was so funny to find he had just discovered Mystery Science Theater 3000, and was losing it watching The Giant Gila Monster. I sat down to watch. I didn’t really get it then, but I’ve been a fan ever since.
I’m not sure if you count RiffTrax (it’s all the same guys), but their commentary for The Last Airbender (2010) and Twilight leave me in tears every time.