I would say nothing that never reaches the break even point between investment and increased productivity (or what ever the gain is).
The problem is you often don't know it beforehand and therefore in my opinion something you definitely want to learn is how to fold a bad hand (or skill).
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I would say nothing that never reaches the break even point between investment and increased productivity (or what ever the gain is).
The problem is you often don't know it beforehand and therefore in my opinion something you definitely want to learn is how to fold a bad hand (or skill).