Don't nurse if you might drop your baby
Anyway, the most interesting things she said regard alcohol. She was talking about how quickly our bodies metabolize alcohol and there's no reason to pump and dump (which I already knew). But she said that our breasts are able filter out toxins and poisons, much like the liver, and only very little alcohol gets into our milk at all. She said the only reason you shouldn't nurse your baby due to alcohol consumption is if you think you might drop your baby.
I personally would not be comfortable nursing drunk, and will continue to offer pumped milk instead if I need to. But the idea that breasts filter alcohol makes a lot of sense to me.
(She also said some really fascinating things about drinking and caffeine intake during pregnancy.)