Bugs lurk in corners and congregate at boundaries.

A design remedy that prevents bugs is always preferable to a test method that discovers them.

Software never was perfect and won't get perfect. But is that a license to create garbage? The missing ingredient is our reluctance to quantify quality.

Extra features were once considered desirable. We now recognize that 'free' features are rarely free. Any increase in generality that does not contribute to reliability, modularity, maintainability, and robustness should be suspected.

First law: The pesticide paradox. Every method you use to prevent or find bugs leaves a residue of subtler bugs against which those methods are ineffective.

If you can't test it, don't build it. If you don't test it, rip it out.

More than the act of testing, the act of designing tests is one of the best bug preventers known.