You are absolutely right about the danger of knowing your own product too well. On the other hand, a developer is often in a much better position to know how t

You are absolutely right about the danger of knowing your own product too well. On the other hand, a developer is often in a much better position to know how to "make the computer do the work" than the end-user. Ideally, you'd test with both...several times. It would be wonderful if clients were willing to pay for this level of software perfection!