Saturn bought me some good times, Sega fuck ups notwithstanding. 'Do you guys not have phones' has my vote, it was definitely the moment Blizzards's decline was plain for all to see. Imagine being embarrassed like that at your own convention where previously such a thing happening was unthinkable (keep in mind this was years before we all found out how deplorable Blizzard HQ actually was).
Xbox One also had that cringe announcement that still brings me lols but it didn't change my opinion of Microsoft anywhere near like Blizzcon 2018 did.
https://www.youtube.com/watch?v=KbWgUO-Rqcw