"Taking a charge" has gone crazy. "Flopping" has gone crazy. There are two competing realities in the NBA that seem to have made interior defense next to impossible.
First of all, everyone hates flopping. Whether it's the relationship to soccer (and the fact that, at least at first, it was primarily foreign-born players, i.e. those players from soccer-playing countries, who were doing most of the flopping) or some other factor (such as impeding the flow of the game or some inherent un-manliness), flopping draws the ire of the American basketball fan like almost nothing else.
Like the guy in your local pick-up game who calls for passes from the opposing team (and then laughs during his uncontested lay-ups), floppers are unpopular, but only to the opposition. They are, in a strictly strategic sense, good plays. They are low risk (there's usually help defense around) and high reward (if they work, it's a turnover and a foul on the opposing player). They are also the bane of physical players. When no one could figure out how to defend Shaquille O'Neal, they decided to start falling down around him, hoping that offensive fouls would be called. They were rewarded. This practice of rewarding the falling down led to the second reality, which is, in some ways, more frustrating.
In the current NBA officiating climate, you can't take a charge without falling down. This is hyperbole, of course, but there's a (large) kernel of truth in there. Officials are so used to people falling all over the floor that they assume that if someone doesn't fall down, they haven't been fouled. Defenders who take a dropped shoulder to the chest but hold their ground (i.e. "play good defense") are almost never rewarded with charge calls. This, of course, trains defenders to fall down when trying to draw an actual charge and also encourages more flopping.
It's a vicious cycle with relatives on the offensive end: watch Tony Parker play, and he spends as much time lying on the court as he does standing on his two feet. Every time he drives the lane, he ends up on his back, hoping to draw a foul. Offensive flopping has not reached the point of defensive flopping, because officials don't yet believe that one has to fall down (or jerk one's head back as though shot with a deer rifle...ahem, Dwyane Wade) to have been fouled. But it's on the horizon.