Sidney Poitier's crowning moment of awesome as an actor is indisputably the moment when his character, Det. Virgil Tibbs, is slapped across the face by the rich white bigot, Endicott, for daring to question the latter on suspicion of murder. To the shock of white viewers and the delight of Black ones, Tibbs instantly slaps Endicott right back, an act that was previously unthinkable for African American characters in mainstream Hollywood films. There's a Meaningful Background Event throughout the scene where Endicott's servant, also a Black man, watches the whole thing unfold. You can see him flinch in fear at how his boss—or Police Chief Gillespie, who also witnesses the exchange—might retaliate when Tibbs slaps him back. But, after Tibbs manages to leave without consequence, the servant gives an "I pity you" look to his boss before also leaving. It isn't just the slap that sends Endicott into tears; Tibbs has completely humiliated and emasculated him in front of someone he ostensibly has authority over. Someone who now realizes that he's been scared of a complete loser this whole time. It's an iconic moment of unapologetic Black badassery, and proved a huge influence on the Blaxploitation genre as it developed over the following decade.
Tibbs gets another awesome moment (one that went down in history as one of film's greatest lines—there's even a trope named after it) when he casually produces evidence that disproves Chief Gillespie's theory about the recent murder. Gillespie, furious at being shown up by a Black man, unloads on him, and...
Gillespie: Well, you're pretty sure of yourself, ain't you, Virgil? "Virgil," that's a funny name for a nigger boy that comes from Philadelphia! What do they call you up there?
Tibbs: They call meMister Tibbs!
Gillespie himself gets one when he rescues Tibbs from an angry mob of racists, authoritatively, by slapping one and gut-punching another — left-handed. Despite him having wanted Virgil to leave in the first place.
In the film's climactic scene, Tibbs talks his way out of getting shot/killed by a second angry mob by getting the mob leader to realize his sister was at an abortionist's with the man who really got her pregnant.
