It's all about riding the line between human touches and sloppy. What's a positive addition and what takes away from the focus of the song. That one bass note that hangs slightly too long but pulls you into the bridge could be great. 45% of the bass notes not in the groove is sloppy and distracting. Catching someone on a mic after a chorus or at the end of the song saying "Alright, that was the one" could be cool if you left it in, but if it's one of 28 hot mic things that pop up in the mix it's just a distraction, and not good. That bass track in the earlier post was 95% perfect but I went and "fixed it anyway as a good base to start from, and have an easier time making decisions. There are already a couple of places where I'm going to drag the extra hang of the note back because it sounds better than being right on time. Some mistakes can make a track (some "mistakes" are deliberate to help make the track), and these days if it makes it onto a record, even if it was a genuine mistake, it was a conscious decision to keep it. But most of the time they're just mistakes. The trick is recognizing when you got a moment on the recording, and keeping it, vs. ending up with a production with too many distracting errors that makes the listener skip to the next track.