Again, the book Test-Driven Development: By Example by Kent Beck provides me with an eye-opening experience. It explains how test-driven development is useful for scope control when developing.
The thought popped up into my mind a while ago, that there is actually a striking similarity between refactoring and performance optimization.
When I read Ron Jeffries Soduko articles, I was wondering why he was writing such sloppy unit tests. He didn’t seem to test even half of the code he wrote. A short email conversation later I had realized that he of course wasn’t sloppy, but rather just much more clever than I was (not that surprising, really). 
Visual Basic 6 programmers are protected from the “real world”. The upside is that VB programmers really can get much more useful things done in less time, the downside is that there are limits for what you can do in VB… and the fact that VB’s behavior sometimes can be really, really strange.