The line comes from the built-in bots in Counter-Strike, Valve's team-based tactical shooter that defined early 2000s PC gaming. The bots used short, text-to-speech style voice reactions for in-game events, and players ripped these dry one-liners onto soundboards. Oh Boy became a favorite because its resigned tone fit failed plays perfectly. It spread through frag movies, Twitch clips and meme compilations, and it endures as shorthand for gaming disappointment among Counter-Strike and CS2 players.