[amelius]

In my opinion the biggest reason why writing software is hard is that the requirements are often not clear from the beginning. Changing requirements can kill a software project. What makes it even harder is when data has to be migrated during the process.

Analogy for clueless manager types: in many cases, software is 99% plumbing. But imagine the cost of changing the plumbing after the house has been built :) Also consider the problem of changing the plumbing while people are actually living in the house.