The interface of git seems to assume that you're familiar with the underlying concepts. The official docs and tutorials are pretty good nowadays, but I can see how the interface itself really doesn't give you many clues. (I was already familiar with hg when I started using git, so I picked it up quite quickly.)

Coming up with a newbie-friendly interface has probably been a much, much lower priority than getting the underlying system working well, which is pretty typical of Unix culture. Writing good GUIs can be quite hard, and moreover, takes a very different skill set than most programming does. (GUIs like this (http://www.ok-cancel.com/comic/4.html) are ... not helpful.)

> The biggest thing that would be needed, however, are some better error messages.

While I emphatically agree with you, in all fairness, everything needs better error messages. (Have you ever used OCaml? Yeesh!)