The fastest you found out you hated a game

[Syl4r]

Approx 3 minutes in guitar hero. Right after i finished my first song, i realized tapping buttons in rhythm wasn't as fun as it was made out to be. Thank god i didnt buy it and was only borrowing it

 

[Revolutionary]

Two worlds/ 10 minutes (including cutscene)
It was just trying and failing to be oblivion.