Whats the most important aspect of badminton?

What do you guys think in your opinion is the most important aspect of badminton? Footwork? Positioning? Precision? Power? Speed? Etc (ofc everything is important and being all around player) but ones something that is so important it could elevate your entire game even if your not the best?

And if so, what would be good drills i could do by myself for that?

And whats another underrated skill to learn that everyone seems to overlook?