In a few words

Computers are useless. They can only give you answers.” (Pablo Picasso)

The only people who have anything to fear from free software are those whose products are worth even less.” (David Emery)

If debugging is the process of removing bugs, then programming must be the process of putting them in.” (Edsger W. Dijkstra)

A computer lets you make more mistakes faster than any invention in human history–with the possible exceptions of handguns and tequila.” (Mitch Radcliffe)

More in 101 Great Computer Programming Quotes, via Peter Forret.