A huge no-no in music theory.
Me: I decided to write a four-part harmony and I put a whole bunch of parallel fifths because why not!!!!!!!!!
Mom: YOU'RE GROUNDED GROUNDED GROUNDED GROUNDED GROUNDED FOR 431460316437164738201648316478301643701432143214321432143214321432143124 GOOGOLPLEX ETERNITIES!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!