You live only once The logician would argue, You only live once should be rewritten as You live only once, with only next to the thing it qualifies, once. The logician would be unbearably pedantic, but there is a grain of good taste in the pedantry. Writing is often clearer and more elegant when a writer pushes an only or a not next to the thing that it quantifies. In 1962 John F. Kennedy declared, “We choose to go to the moon not because it is easy but because it is hard.” That sounds a lot classier than “We don’t choose to go to the moon because it is easy but because it is hard." Steven Pinker, The Sense of Style grammar
Materials and how to employ them Forming a paper clip presents a common dilemma encountered by engineers and inventors: the very properties of the material that make it possible to be shaped into a useful object also limit its use. If one were to try and make a paper clip out of wire that stayed bent too easily, it would have little spring and not hold papers very tightly. On the other hand, if one were to use wire that did not stay bent, then the clip could not even be formed. Thus, understanding the fundamental behavior of materials and how to employ them to advantage is often a principle reason that something as seemingly simple as a paper clip cannot be developed sooner than it is. Henry Petroski, The Evolution of Useful Things Ideas behind their time material