This is the song people point to as the exact moment when The Beatles stopped being a pop group and started being something more. That may be overly simplistic, but it’s definitely a game-changing song. It was the first Beatles single with a harmony too complex to easily play live or mime to on TV. It’s not that it couldn’t be recreated live – Paul McCartney regularly plays it today – but that with the screaming and chaos, it just wasn’t worth it. It was also an adventures new step forward lyrically, McCartney’s response to critics who accused him of only writing about love. McCartney does have an affinity for only writing about love, to this day, but at the time, so did everyone else. The Beatles quickly proved that they could whip up a brilliant pop song about literally any random thing, and other songwriters followed suit, thus making the pop charts one hell of a lot less thematically monotonous.