1. Why did not you find that bug during testing cycle?
2. Why is testing taking so long?
3. Why did not you automate the damn thing?
I have answers for all three questions but Michael Boloton, the testing genius in our era, explained the answer for question 2 with some great examples. I would recommend this to be a must read for anyone work in software engineering.
Study the facts given by Michael. You will realize the truth of test estimation and traditional way of managing test processes.