I'm the kind of guy that buys a new gadget, ignores the manual and just starts to play with it. The same with software. If you need a manual to use it, then it's not intuitive enough. However, as things get complexer and more feature rich, it gets harder to simply discover all the useful features; it took me about 3 months before I accidentally discovered that my new iPod classic has a nifty context menu if you hold down the center button more than a second.

This is what manuals and books are useful for. To find the features you haven't discovered yet, but that turn out to be extremely useful.