矯角殺牛 fix the horn and kill the bull

矯 (straighten) 角 (horn) 殺 (kill) 牛 (bull)

So you do end up burning the house to roast the pig, even if burning the house down is the last outcome you expected.

You notice a defect.
You want to fix the unsightly flaw immediately with a one-step remedy. You don't think it through to get at tough medicine that should cure the fundamental problem.

Your simplistic prescription ends up killing the animal. Needlessly.

You've killed the bull.

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The simplified version of the character 殺 (kill) is 杀.