About the use of language: it is impossible to sharpen a pencil with a blunt axe. It is equally vain to try to do it with ten blunt axes instead. - Edsger W. Dijkstra

We must be very careful when we give advice to younger people: sometimes they follow it!

The major cause [of the software crisis] is that the machines have become several orders of magnitude more powerful! To put it quite bluntly: as long as there were no machines, programming was no problem at all; when we had a few weak computers, programming became a mild problem, and now we have gigantic computers, programming has become an equally gigantic problem. In this sense the electronic industry has not solved a single problem, it has only created them, it has created the problem of using its products.

Program testing can be a very effective way to show the presence of bugs, but it is hopelessly inadequate for showing their absence.