Henry Petroski said this quote

Because they are so humbled by their creations, engineers are naturally conservative in their expectations of technology. They know that the perfect system is the stuff of science fiction, not of engineering fact, and so everything must be treated with respect.

~ Henry Petroski

Engineering is achieving function while avoiding failure.

~ Henry Petroski

The paradox is that when we model future designs on past successes, we are inviting failure down the line; when we take into account past failures and anticipate potential new ways in which failure can occur, we are more likely to produce successful designs.

~ Henry Petroski

Case studies of failure should be made a part of the vocabulary of every engineer so that he or she can recall or recite them when something in a new design or design process is suggestive of what went wrong in the case study.

~ Henry Petroski