The invisible hand is an oft-used metaphor for the free market.

Aesthetics aside, if you train your quads while neglecting your hamstrings, you're setting yourself up for an eventual injury.

The best way to describe the supremum of S is to say that it wants to be the greatest element of S. In fact, if S has a greatest element, then that element is the supremum.

The Kladd and Night Hawk staggered off with their burdens, and the Klan square opened and swallowed them up. In a moment they were both back. “Attention!” the Kladd bellowed. “Fall in—single file, right hand on the shoulder of the man in front of you!”