Chemistry can be a good and bad thing. Chemistry is good when you make love with it. Chemistry is bad when you make crack with it.

The line plays on the double meaning of “chemistry”: the interpersonal spark between people and the literal science of chemical reactions. Sandler’s joke contrasts a socially celebrated outcome (“chemistry” that leads to sex/romance) with a socially destructive one (using chemistry to manufacture crack cocaine). The humor comes from the blunt moral polarity—good versus bad—delivered in a simple, almost childlike structure, and from the abrupt shift from intimacy to illicit drug production. As a comedic aphorism, it also gestures at a broader point: tools and knowledge are ethically neutral, while human intentions and applications determine whether outcomes are beneficial or harmful.