The fact that I can spend ages getting Ganon or Ike up to 150% (I play TL and Kirby), only to be side smashed at 55% and consequently lose. But you know, them's the breaks when you play a light character. I don't mind it really.
But what I truly can't stand is arrogance, both in life and smash. I'm a pretty chill guy most of the time (I do hate losing but I get over it pretty fast. I'm a mediocre player at best so I'm used to it, after all!). But arrogance just grinds my gears.
The other day I played this japanese Mario and he whomped me- it was like he was everywhere. Frankly it was incredible. I was a bit annoyed but mostly amazed at his skill when I lost my first stock- and then he taunted twice in a row.
All appreciation was forgotten. A smoky red haze of pure rage descended upon my being as I imagined him lounging there, with his head slightly cocked and one leg thrown over the leather armrest of his wingback chair, smugly surveying his screen and gently depressing his D-pad twice with slim, manicured fingers. "Yeah, that's right, I'm better than you. Waay better. Stick to your day job, kid."
Enveloped by paroxysms of fury I rematched him again and again, nearly winning a couple of times but never quite cinching it. And every time he robbed me of a stock it was the same thing- Mario would take off his stupid hat and do that stupid twirl and softly utter those gentle, mocking words: "hoohoo".
Twice.
I've genuinely never been so angry in my entire life. If he was in front of me I would've attacked him. Maybe it's childish, but a single taunt is fair enough- you did trample me after all. But two is another level. A level of aggressive cockiness that jams itself in your face, clamoring for you to examine your own failure in excruciating detail. It's more than a taunt, it's an assault on your self-worth, and in my eyes an unforgivable slur in my version of "Smash etiquette".
Everybody has that little tic I suppose, and it turns out that that is mine.
Also, I have a bit of a thing about honour. If someone kills themselves by accident I'll always do the same so we're back on equal footing. Mostly people will give a little thankyou taunt or a few bops and I'll return it, and then we can start fighting again in earnest. But sometimes people will just take advantage, and that makes me sad.