GG comes from early online multiplayer gaming in the 1990s, where players typed good game in chat at the end of StarCraft and Quake matches as a sign of respect. The abbreviation spread to shooters, MOBAs and fighting games and became standard end of match etiquette. Said out loud in streams and edits, it now carries both meanings, sincere respect for a close game and ironic gloating after a one sided win, which keeps the short clip useful across gaming communities.