This is basically the second half of the Robustness Principle[1]:<p><pre><code> Be conservative in what you do, be liberal in what you accept from others.
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If you use both halves things get even better. For example this is why digital electronics work — circuits are forgiving about the voltage ranges of their inputs but very precise about their outputs.<p>It's also a nice way to live life :'(<p>[1] <a href="http://en.wikipedia.org/wiki/Robustness_principle" rel="nofollow">http://en.wikipedia.org/wiki/Robustness_principle</a>