Playing drums while reading notations is like driving while looking at GPS maps
Turning on navigation and not looking at map is like listening to the song so you can play simultaneously
Driving fast is possible only when you have driven before, know the next turn. Same goes for a complex song.
And then many a times relying solely on GPS can lead to bad roads. Likewise, notations can be incomplete. Use your own experience and judgement... Too.
#Analogy
