&quot;The only intuitive interface is the nipple. After that, it&#x27;s all learned.&quot;<p>(Discussion on who coined this phrase at <a href="http:&#x2F;&#x2F;www.greenend.org.uk&#x2F;rjk&#x2F;misc&#x2F;nipple.html" rel="nofollow">http:&#x2F;&#x2F;www.greenend.org.uk&#x2F;rjk&#x2F;misc&#x2F;nipple.html</a>)