The Software Tester’s Axioms [via Michael Kaplan]:
Axiom I: If you have not tested it, assume it is broken.
Axiom II: If someone changes it, they probably broke it.
Axiom III: Sometimes when it is not changed, it breaks too.
Axiom IV: What is broken on the test machine often works fine on the dev machine.
Axiom V:There is always another bug that a user can find.