When someone is new to a game and gets really good RNG, so they think it's all skill not luck.
Especially big in singleplayer games since no one is there to trash talk.
Person 1: "Jim just got to goldrank yet he just started playing last week"
Person 2: "Have you seen the way he plays? All luck, no skill. Bet he's feeling "I'm So Good-itis" right now.
When you think you're so skilled, but in reality it's your teammates/characters that are doing all the heavy lifting. Resorting in you falling behind.
Josh: "wow I thought this game was supposed to be hard, I've cleared 11 stages already! I'm the best at this game". In reality Josh pulled a 5 star hero early on.
Josh was later on team wiped on stage 15, for disregarding lobby upgrades, and for not paying attention to his hero's needs/upgrades; Thus he has I'm so good syndrome.
Fogey/fogy /fougi/ sl. (early 18C+, orig. Scot) old-fashioned, stuck-in-the mud.
Person with old fashioned ideas which he is unwilling to change: Come to the disco and stop being such an old fogey!
You think me an old fogeyand an old tory, his thoughtful voice said. I saw three generations since O’Connel’s time. I remember the famine. Do you know that the orange lodges agitated for repeal of the union twenty years before O’Connel did or before the prelates of your communion denounced him as a demagogue? You fenians forget some things. (James Joyce, Ulysses. PenguinBooks,1992. p. 38)