Sports like pro wrestling have defined villains. The NFL had authentic villains like Jack Tatum and Vontaze Burfict. The NBA, NCAA, on down have misanthropic amateurs by comparison.
Don't say there's no place for toughness. We know "the game honors toughness." Forget about "fake toughness," the "hold me back," snarling, "I'm calling my big brother" imitation.
There's "losing your mind" one-offs ("that's not who I am"), competitive cauldron blowoffs (chair throwing, clipboard smashing), and a few bad actors with personality disorders who shouldn't be playing or coaching.
Unchecked parts of the problem are "enablers" who worship money (e.g. the NCAA) and winning (most of us). Enablers let outlaw programs off the hook over and over or find scapegoats. Enablers at "basketball royalty" schools let player discipline infractions slide, because they can. We know who they are. It's a devil of a problem.
Be aggressive, not dirty. Flying elbows, moving screens, and 'dead legs' aren't part of the game. Not saying an opposing coach taught that, just tolerated it. "Keep hitting her, the refs can't call it every time." Outstanding life lesson for your players, Coach.
Poor sportsmanship is a form of villainy. Run it up by pressing with big leads with your starters against reserves. That's rank not earning ranking. Lose graciously. "We would have won if we made shots." So would we.
Rarely, there's officiating villainy, like Tim Donaghy.
I've heard of an official carpooling members of the home team and I've seen officials on a local youth basketball team go full on "homer" by allowing egregious violations and fouls. The opposing point guard went full on "Heisman" to push defenders away with no calls. And the officials told me to "sit down and shut up" afterwards.
Don't be an accidental villain, diving at a player wiping out an ACL in the final seconds of a blowout (seen that).
Lagniappe: Kids, don't listen to me. Listen to him.