Our greatest shortcoming is our inability to understand the exponential function
Before people freak out about exponential growth, please consider John McCarthy's Slogan. (Yes, <i>that</i> John McCarthy; Lisp isn't the only thing he's done.)<p><pre><code>  He who refuses to do arithmetic is doomed to talk nonsense.
</code></pre>
<a href="http://www-formal.stanford.edu/jmc/progress/index.html" rel="nofollow">http://www-formal.stanford.edu/jmc/progress/index.html</a><p>Based on reactions to this video (among other things), I'd add Hartl's Counterpoint:<p><pre><code>  Just because you're willing to do arithmetic doesn't 
  mean you're not talking nonsense.
</code></pre>
In case you're wondering <i>why</i> you shouldn't freak out, I offer you this: <a href="http://en.wikipedia.org/wiki/Logistic_function" rel="nofollow">http://en.wikipedia.org/wiki/Logistic_function</a>