Yoda teaches the right development attitude

One of the best articles about the attitude a developer should have, was posted by Ted Neward at his blog - The Mountain of Worthless Information.
Seams like Yoda is one of the best teachers ever.

Luke: All right, I'll try.
Yoda: (emphatically) NO. Do, or do not. There is no try.

Ted: (emphatically) NO. The system is, or it is not. There is no should.

So never say: "The system should ...".
Instead ask yourself: "What are my assumptions and do they always hold, or is there a flaw somewhere?"
This way you will find the truth.

PS: This works only in a non Microsoft based development environment. If you develop MS Access never make the assumption of a functioning system.