The Beatles weren't at all sloppy for the time. It wasn't that they could do no wrong. They were making great music, and moving the goal posts forward with each recording, innovating with both their songs and their sonics. The elements might not always have been perfect, but they came together to create a great end product. They're a good argument against chasing perfection, a la Mutt Lange, who has been known to record individual strings in guitar chords.