In one respect, playing defense is incredibly simple.
Keep your man in front of you, guide players to the help, rotate to help the helper and scramble to close down passing lanes. That all sounds so simple.
Of course, it is hardly that simple. The offense has every advantage in the league these days. It is extremely hard to bump and take guys off their spots. And even with a hand in their face, there are plenty of players who can make tough shots.
Building a team with the defense as its backbone is a hard thing to do in this league.