It's no secret at this point that Draymond Green is a really emotional guy. He puts his heart on his sleeve and is prone to letting all his emotions show on the court whether positive or negative. When the game is going well this can spark the entire team into an emotional fire that carries them to victory. When it's going bad, well...situations like last night happen.
During a huge collapse, that resulted in Golden State's eventual loss, the Warriors had a chance to seal the game away. The play they "drew up" was less than spectacular, and Green made his thoughts on it well known mid-play.
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This was a disaster from the start. Durant calls for the ball and there's immediate hesitancy by Curry to let him have it late. This must have broken whatever play Golden State had originally planned to run, because as soon as Durant touched the ball Green lost his mind. First he starts yelling in Curry's direction, and then he goes off and stands in the corner looking visibly irate. Curry on the other hand seems equally displeased with the situation attempting to set a screen of some kind before giving up and choosing to spot up on the wing.
If Durant had made the shot obviously all would have been forgiven, but in this situation there appears to be some merit to Green losing his mind about Durant taking the ball here. The play they ran failed and it involved absolutely nobody besides Durant which is awful late game management from Golden State.