I like the way Zach Weiner over at SMBC put this:<p>&gt;A human is only happy if she has two, and everybody else has one.  And even then, she starts imagining three.<p>(<a href="http:&#x2F;&#x2F;www.smbc-comics.com&#x2F;?id=3531" rel="nofollow">http:&#x2F;&#x2F;www.smbc-comics.com&#x2F;?id=3531</a>)