Insecticide resistance genes are useful when there's insecticide about, but not when there isn't: then, they can be detrimental.

抗药性在有杀虫剂的地方有用，但是在没有杀虫剂的地方就没什么用了：有时甚至是有害的。

youdao

I began to think how ridiculous it is that our most useful allure is resistance and that our natural reaction is to push away someone who shows that he CARES.

我开始想这是有多滑稽。我们最管用的魅力是拒绝，我们最本能的反应是推开那些表现出关心我们的人。

youdao

Expression of negative emotions is always mechanical, so it can never be useful, but resistance to it is conscious.

负面情绪的表达总是机械性的，所以永远也不可能有用，但是抵抗它却是有意识。

youdao

One can only wonder how much faster progress on tax reform or school choice would have been if the political capital devoted to income inequality had been devoted to fighting entrenched institutional resistance to useful reforms.

WSJ: Jenkins: The Inequality Obsession