Stay angry. That’s J.R. Smith’s message to Iman Shumpert, who admitted Friday he is “[mad] at the world,’’ then took it out on the Garden rim with a violent right-handed driving dunk against the Magic that had the arena rocking and the iron shaking. “That’s when Shumpert plays his best, when he plays angry and [has] a chip on his shoulder,’’ Smith said. “That’s when he succeeds the most. He should keep playing like that. He should always play like that. He’s the guy with the most energy on the team. For him to be a defensive guy and make offensive plays like he did the last couple of games, that’s a hell of a combination.’’ Shumpert scored a season-high 17 points against the Nets, draining five of seven 3-pointers. Against Orlando, he scored 10 points on 4-of-9 shooting with four defensive rebounds and created several fast break opportunities. He looks nothing like the lost soul that appeared to have quit on coach Mike Woodson in Portland two weeks ago. Indications are President Steve Mills hasn’t found a good trade for Shumpert, since the Knicks would want a significant frontcourt asset in return. The Knicks have a shooting-guard glut Woodson is slowly figuring out, spreading minutes between Shumpert, impressive rookie Tim Hardaway Jr. and Smith.