Plus, if it's as much work to create a diagram as it is to do much of the programming (not to mention maintaining it), you're just not going to do it. One type

Plus, if it's as much work to create a diagram as it is to do much of the programming (not to mention maintaining it), you're just not going to do it. One type of diagram I have found to be truly useful, though, is the sequence diagram. I needed to integrate someone else's library into my application, and having this was a huge help. If anyone has a pointer to a good sequence-diagram generator (that runs on Mac, preferably), I'd be happy to hear about it!