Hard to pick one...
first time i played the game (1999) i beat it fast, like unlock falcon fast, and made some sort of celebratory noise. My mom, who had just dropped $50 (i think?) on the game was like "already?!" upset at how quickly her money was burned through. Don't worry mom, I got my money's worth lol.
Apex 2012 was just awesome in general, the crew of me, jimmyjoe, boom, jaime, randomBrawlNoob, Knitephox and I'm sure I'm forgetting 1 or 2 people was amazing. Then it snowed and I used it as an excuse to stay for a few extra days
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I probably had the most fun at this apex out of any of them even though the other ones had a lot more players. It was the first tourney for me so literally everything was new and exciting. Plus I sucked even more **** back then at the game than I do now to start, so I learned tons and went from low C tier to being able to take some games off of Jaime.
Apex 2012 first time I played sensei on console (first day, I was still low c tier), beat his fox. He was pissed lol. so he went falcon and wooped me.
apex 2012 playing isai on FD on console courtesy knitephox for a bit, until isai said 'this stage sucks'. knitephox was not happy lol
Apex 2013 was playing boom in hyrule friendlies, he was kirby, I was pikachu. On the long middle platform he utilted and I usmashed and we clanked from a quarter of the platform away. Maybe the funniest in game moment I've ever had.
Meeting all the international people is a really cool experience. I like talking with the japanese even though its mostly gestures and smash terms, its fun lol.
smashing with the mexican/brazilian crew at apex 2014 and learning tacos jab technology counter banze counter
too many more to count...