enough it deserves to be mentioned multiple times. There are so many nuances to it though. When the post player can barrel his shoulder into the defender, and the defender gets a foul call for holding his ground. When the defender cuts of the lane of the ball handler and the offensive player has nowhere to go (Exum vs Lillard the other night). When the offensive player gets by his guy, then leans into the defender to create space with his inside shoulder ( McCollum and Harden do this a ton) it's a foul on the defense (should be a no call imo unless they extend the arm then offensive).