When we talk about "finding a happy medium," we're referring to striking a balance between two opposing forces or ideas. Antonyms for this phrase might include "extreme," "overindulgence," or "excess." In each of these cases, we're talking about going too far in one direction or the other, rather than finding a balance that works for everyone involved. Other antonyms might include "stubbornness," "rigidity," or "inflexibility," which all suggest an unwillingness to compromise or consider multiple perspectives. Ultimately, finding a happy medium is about being willing to listen to others, weigh different options, and find a solution that works for everyone, which is always preferable to the alternative of extremes or inflexibility.