Derrick Williams has so many plays where he simply is clueless out there.
On offense : DMC is in the paint, double-teamed with a third (Tyreke) hovering nearby. Instead of backing away and getting in the opposite corner and wait for the kick-out if DMC gets stopped, DWill chooses to go forward, into the middle of the lane for some inexplicable reason. (BTW - McCallum stayed bolt still on that play, and never sidled down to DMC's side corner 3 to give Demarcus the easy assist. He stayed up top, which is where Omri inexplicably snuck over to from his 5 o'clock position. The whole team seems oblivious as to where to stand for open 3 ptrs. I've never seen a team this braindead on offense - nobody else in the league has this many people incapable of going to the open spots for 3's.)
On defense : DWill has no clue how to block his man out off the rebound. Not only does he not know where his man is, but he doesn't position his body remotely in a place that he could interpose between the rim and his man.
Similarly, what was the point of him lazily pushing AD in the chest while he shot? Does he really think that will affect the shot?